Chapter 2 Mineralogy PDF

LESSON1: ELEMENTARY KNOWLEDGE sometimes muscovite mica form at ON SYMMETRY OF around 750°–800°C. CRYSTALLOGRAPHIC SYSTEMS Norman Levi Bowen: Crystallization Process of...

LESSON1: ELEMENTARY KNOWLEDGE sometimes muscovite mica form at ON SYMMETRY OF around 750°–800°C. CRYSTALLOGRAPHIC SYSTEMS Norman Levi Bowen: Crystallization Process of Igneous A pioneering geologist who studied Rocks: magma cooling. In 1912, he joined the Carnegie Minerals in igneous rocks crystallize Institution in Washington, D.C., at different temperatures. where he carried out groundbreaking Magma can remain partly liquid experimental research into the while crystals form. processes of cooling magmas. His experimental work at the Bowen’s Reaction Series Carnegie Institution led to the creation of the Bowen reaction The sequence in which minerals series. crystallize from a magma. His experiments involved melting rock to magma, cooling it at various Bowen’s Reaction Series (Discontinuous stages, and analyzing the Branch) crystallized minerals. *Minerals are replaced entirely as they react and transform with cooling. Comparison of Mafic vs. Felsic Magma: Olivine is the first mineral to crystallize (1200°C–1300°C). 1. Silicon Dioxide (SiO₂) Content: If silica is present, olivine reacts with it to form pyroxene as temperatures Mafic magma: 45%–55% SiO₂. drop. Felsic magma: 65%–75% SiO₂. Further cooling leads to the Difference: Felsic magma has formation of amphibole, then significantly more silicon dioxide, biotite. making it more silica-rich. Sequence: Olivine → Pyroxene → Amphibole → Biotite. 2. Iron, Magnesium, and Calcium Oxide (FeO, MgO, CaO) Content: Bowen’s Reaction Series (Continuous Branch) Mafic magma: 25% FeO, MgO, and CaO. *A single mineral (plagioclase) forms but Felsic magma: Only 5% FeO, MgO, gradually changes its chemical composition and CaO. without altering its crystal structure. Difference: Mafic magma is much richer in iron, magnesium, and Plagioclase feldspar begins to calcium, giving it a darker color and crystallize around the same time as higher density. pyroxene. Initial plagioclase crystals are 3. Sodium and Potassium Oxide (Na₂O, calcium-rich (anorthite). K₂O) Content: As temperature decreases, plagioclase becomes more Mafic magma: 5% Na₂O + K₂O. sodium-rich (albite) if sodium is Felsic magma: Around 10% Na₂O + available. K₂O. Difference: Felsic magma has more Zoned Plagioclase Crystals: sodium and potassium oxides, contributing to its lighter color and Some plagioclase crystals develop a lower density. zoned structure, where the center is calcium-rich and the outer parts are Summary: sodium-rich. If the magma is silica-rich, Mafic magma is rich in iron, potassium feldspar, quartz, and magnesium, and calcium, with lower silicon dioxide and alkali metal  content. It forms darker, denser 1. Zircon rocks (e.g., basalt). 2. Monazite Felsic magma is rich in silica and 3. Apatite alkali metals (sodium and 4. Titanite potassium) but has lower iron, 5. Tourmaline magnesium, and calcium. It forms 6. Pyrite (and other opaques) lighter, less dense rocks (e.g., granite). *Accessory minerals are rare but vital for understanding rock history and composition. Intermediate magma a type of magma that has a chemical composition between mafic and Mineral Composition and Earth's Crust felsic magmas. It represents a middle ground in terms of silica Eight elements make up 98% of content and mineral composition. the Earth's crust: 1. Oxygen (O) 2. Silicon (Si) 3. Aluminum (Al) 4. Iron (Fe) LESSON 2: PHYSICAL PROPERTIES OF 5. Magnesium (Mg) MINERALS 6. Calcium (Ca) 7. Sodium (Na) 8. Potassium (K) Minerals *The elemental composition of minerals is A naturally occurring substance, closely related to the Earth's crust and the usually solid, crystalline, stable at parent rock’s chemical makeup. room temperature, and inorganic. Rocks are composed of minerals There are almost 5000 known mineral species. However, most Formation of Minerals from Igneous rocks are formed from combinations Processes of a few common minerals called Mineral composition in rocks rock-forming minerals. depends on the chemistry of the parent body/magma. ○ Magma rich in Iron and Rock-Forming Minerals Magnesium (found in basalt) → forms minerals like olivine These minerals are abundant and form the and pyroxene. majority of rocks: ○ Magma rich in Silicon (found in granite) → forms 1. Feldspars silica-rich minerals like 2. Quartz feldspar and quartz. 3. Amphiboles Mineral-Rock Chemistry 4. Micas Relationship: 5. Olivine ○ Minerals tend to form in 6. Garnet rocks where the bulk 7. Calcite chemistry matches their 8. Pyroxenes composition. ○ Example: Andalusite *Rock-forming minerals are common and (Al₂SiO₅) is unlikely to be create the bulk of most rocks. found in aluminium-poor rocks like quartzite. Accessory Minerals *Magma composition controls the types of Occur in rocks in small quantities. minerals that form during igneous Provide valuable geological history processes. of a rock, (e.g., rock age). Examples: PHYSICAL PROPERTIES OF MINERALS  Minerals can be identified based on The following list gives examples of different their physical properties, though some crystal habits and examples of common require a petrographic microscope or by minerals that may exhibit each habit. complex analytical techniques for precise identification. Acicular – Granular – Since no single property can reliably needle-like, e.g. aggregates of identify all minerals, it’s best to use multiple natrolite, rutile crystal, e.g. bornite, diagnostic criteria, often with the help of a scheelite hand lens for clarity. Bladed – Hexagonal blade-like, slender -six-sided, e.g. ❖ COLOUR and flattened, e.g. quartz, hanksite one of the most noticeable kyanite features of a mineral but often unreliable for Botryoidal – Massive – no identification. grape-like masses, distinct shape, e.g. Many minerals can appear in e.g. hematite, turquoise, realgar malachite various colors due to impurities or slight changes Columnar – long, Octahedral – in composition. slender prisms, e.g. eight-sided, e.g. Examples: calcite, gypsum diamond, magnetite ➔ Corundum (Al₂O₃) can form Cubic – Platy – flat, tablet as ruby (red due to cube-shaped, e.g. shape, e.g. chromium) or sapphire pyrite, galena, wulfenite (commonly blue, but also halite found in yellow, orange, pink, green, and brown). Dendritic – Prismatic – ➔ Garnets exhibit a wide range tree-like, branching elongate, prism in multiple like, e.g. of colors, depending on their directions, e.g. tourmaline, beryl composition. They can be pyrolusite, native found with virtually any copper, native silver colour, with blue being extremely rare. Fibrous – very Radial or Stellate slender prisms, e.g. – radiating asbestos, tremolite outwards from a *therefore advisable not to rely on central point, colour alone to identify a mineral. star-like, e.g. wavellite, ❖ CRYSTAL HABIT pyrophyllite Crystal form refers to the characteristic shape of a Foliated or Lamellar – layered mineral's crystal or crystal structure, parts aggregate: easily into very thin ➔ Euhedral: Crystals with sheets, e.g. well-developed faces (e.g., muscovite, biotite garnet crystals). ➔ Aggregates: Minerals that ❖ HARDNESS appear as groups or masses a measure of how resistant a of crystals rather than mineral is to scratching individual, well-defined controlled by the chemical crystals (e.g., asbestosis composition and structure of usually found as an the mineral aggregate of very fine fibres). commonly measured on the Mohs scale *Crystal form can help in identifying This is defined by ten minerals, but like color, it should be minerals, where each mineral used in conjunction with other can scratch those with a properties. lower scale number *Diamond (hardness 10) can scratch everything below it on the Mohs scale, but cannot itself be scratched,  whereas quartz (hardness 5) can diamond, cerussite, cubic scratch calcite (hardness 3) but not zirconia corundum (hardness 9). ➔ Dull or Earthy – no reflections; e.g. kaolinite ➔ Greasy – the appearance of SCALE INDICAT COMMO NUMBER OR N being coated with an oily MINERA OBJECT substance; may also be L S greasy to the touch; e.g. opal ➔ Pearly – the whitish 1 Talc iridescence of materials such 2 Gypsum Fingernail as pearls; e.g. stilbite ➔ Vitreous – like glass; e.g. 3 Calcite Copper calcite, quartz, beryl Coin ➔ Silky – like silk fabric; e.g. satin spar (a variety of 4 Fluorite gypsum) 5 Apatite Knife ➔ Resinous – like a resin; e.g. Blade fire opal ➔ Metallic – metal-like in 6 Orthoclas Window appearance; e.g. pyrite e Glass 7 Quartz Steel File ❖ CLEAVAGE refers to how a mineral 8 Topaz breaks along planes of weakness in its crystal 9 Corundu m structure due to weak chemical bonds. It is a 10 Diamond valuable diagnostic tool and can be classified as: ❖ STREAK ➔ Perfect, Good, Distinct, or refers to the colour of the Poor: Describes how easily mark it leaves behind after the mineral cleaves along being rubbed against a piece these planes. of unglazed porcelain ➔ Cleavage Planes: The ➔ Hematite: Often appears number of directions in which black, silver, or brown-red, a mineral cleaves (1, 2, 3, 4, but its streak is always dark or 6). blood-red. Examples: ➔ Chalcopyrite: Appears ➔ Micas: One cleavage plane golden-brown but leaves a (splits into thin sheets). green-black streak. ➔ Amphiboles: Two cleavage planes. *Streak can be used only for ➔ Calcite (Iceland spar): minerals with a Mohs hardness of 7 Three cleavage planes or less, as minerals with a hardness (rhombs). greater than 7 will themselves ➔ Galena: Three planes (forms scratch the streak plate. cubes). ➔ Fluorite and Diamond: Four ❖ LUSTRE planes. refers to the way in which the ➔ Sphalerite: Six planes. surface of a mineral reflects light Minerals without Cleavage: Quartz lacks controlled by the kinds of cleavage and instead breaks with a atoms present and their conchoidal (shell-like) fracture. bonding ➔ Adamantine – diamond-like *In transparent minerals or in thin sections lustre; such minerals are viewed through a microscope, cleavage usually transparent and have may be seen as a series of parallel lines. a high refractive index; e.g.  ❖ FELDSPAR is the name of a large organization of rock forming silicate minerals that make up over 50% of Earth’s crust. They are discovered in igneous, metamorphic, and sedimentary rocks in all components of the sector. Feldspar minerals have very comparable structures, chemical compositions, and bodily properties. PHYSICAL PROPERTIES OF FELDSPAR Common feldspars consist of MINERAL orthoclase (KAISi3O8), albite (NaAISi3O8), and anorthite ★ ALKALI FELDSPAR MINERALS (CaAI2Si2O8). COMPOSITIONS OF FELDSPAR GROUP MINERALS Feldspar minerals belong to the tectosilicates group and are mainly composed of three endmembers: 1. Potassium Feldspar (K-spar): KAISi₃O₈ ➔ Sanidine is stable at the highest 2. Albite: NaAISi₃O₈ temperatures, and microcline at the 3. Anorthite: CaAI₂Si₂O₈ lowest. Solid solutions form between these ➔ Perthite is a typical texture in alkali endmembers: feldspar, due to the exsolution of contrasting alkali feldspar Alkali Feldspar: A solid solution compositions during cooling of an between K-feldspar and albite. intermediate composition. Plagioclase Feldspar: A solid ➔ The perthitic textures in the alkali solution between albite and feldspars of many granites can be anorthite. seen with the naked eye. ➔ Microperthitic textures in crystals are Limited solid solution occurs between visible using a light microscope, K-feldspar and anorthite. Albite is unique whereas cryptoperthitic textures can as it can be part of both alkali and be seen only with an electron plagioclase feldspar groups. Immiscibility microscope. occurs at temperatures typical of Earth's crust in these solutions. ★ BARIUM FELDSPARS ○ also considered alkali feldspars ○ Barium feldspars form as the result of the substitution of barium for potassium in the mineral structure. ○ The barium feldspars are monoclinic and include the following: Celsian BaAl2Si2O8, Hyalophane BaAl2Si2O8. ★ PLAGIOCLASE FELDSPARS  Feldspar is a common uncooked fabric utilized in: Glassmaking: Feldspar provides alumina, which improves product hardness, sturdiness, and resistance to chemical corrosion of glass. Ceramics: Feldspar's alkalis (calcium oxide, potassium oxide, sodium oxide) act as a flux, lowering the melting temperature and creating a glassy matrix during firing method. Other Uses: Filler in paint, plastics, and rubber. PLAGIOCL PERCENT PERCENT In the U.S., about 66% of feldspar is ASE NaAlSi3O8 CaAl2Si2O used in glassmaking, with the MINERAL 8 remainder used in ceramics NAME (insulators, sanitaryware, tiles, etc.) Albine 100-90% 0-10% and other industrial applications. albite anorthite Oligoclase 90-70% 10-30% ❖ AUGITE albite anorthite Augite is isomorphous with Andesine 70-50% 30-50% Diopside and Hedenbergite, albite anorthite forming an intermediate series between these minerals. It contains Labradorite 50-30% 50-70% additional sodium and aluminum in albite anorthite its structure. Although chemically Bytownite 30-10% 70-90% variable, Augite is classified as a albite anorthite single mineral species by the International Mineralogical Anorthite 10-0% albite 90-100% Association (IMA), though it is anorthite technically more of a group. The plagioclase feldspars are triclinic. The Chemical Composition: plagioclase series follows (with percent Augite is part of the anorthite in parentheses): pyroxene group, with some Albite (0 to 10) NaAISI3O8, variations due to sodium and Oligoclase (10 to 30) (Na, Ca) (AI, Si) aluminum. AISi2O8, Alterations: It frequently Andesine (30 to 50) alters into other minerals NaAlSi3O8—CaAl2Si2O8, such as Hornblende, Labradorite (50 to 70) Chlorite, and Epidote. (Ca,Na)Al(Al,Si)Si2O8, When altered to Actinolite, it Bytownite (70 to 90) (NaSi,CaAl)AlSi2O8, is called Uralite. Anorthite (90 to 100) CaAl2Si2O8. Crystals: Large, lustrous Augite crystals are common ❖ PRODUCTION AND USES OF and sometimes prized by FELDSPAR MINERALS collectors. Etymology: The name In 2010, global feldspar production Augite comes from the reached 20 million tonnes, with Greek word "augites," leading producers being: meaning brightness, referring to its occasional Italy: 4.7 million tonnes bright luster. Turkey: 4.5 million tonnes China: 2 million tonnes  Augite is an important rock-forming Augite does not have any physical, mineral , and large crystals are fairly optical, or chemical properties that make it common. It is a widespread member especially useful. It is therefore one of the of the pyroxene family. few minerals that has no commercial use. The calcium content of augite has been Augite is widely recognized and found to be of limited use in studies of the valued in geological studies and by temperature history of igneous rocks. mineral collectors. QUARTZ PHYSICAL PROPERTIES OF ➔ one of the most well-known minerals AUGITE on earth ➔ occurs in basically all mineral environments, and is the important constituent of many rocks. ➔ Some forms of Quartz, especially the gemstone forms, have their color enhanced ➔ Quartz frequently forms the inner lining of geodes. Most geodes have an inner layer of larger crystalline Quartz, and an outer layer of Chalcedony or banded Agate. PHYSICAL PROPERTIES CHEMICAL FORMULA: SiO2 COMPOSITION: Silicon Dioxide COLOR: Colorless, white, purple, pink, brown, and black. Also, gray, green orange, yellow, blue, and red. Sometimes multicolored or banded. STREAK: White HARDNESS: 7 CRYSTAL SYSTEM: Hexagonal CRYSTAL FORMS AND AGGREGATES: VARIETIES FASSAITE – variety of augite ★ Quartz crystals are unique and very originally described from the Val D’ identifiable with their pointed and Fassa region in Italy which has a often uneven terminations. low iron content. This is usually ★ Quartz crystal habits include drusy, responsible for this variety having a grainy, bladed, as linings of geodes, lighter green color and increased as rounded waterworn pebbles, translucency then other most Augite. radiating, as pointy pyramids on a JEFFERSONITE – varieties of matrix, as dense agglomerations of Augite rich in manganese and small crystals, massive, globular, zinc, found in the Franklin District, stalactitic, crusty, in nodules, and in Sussex Co., New Jersey and amygdules. surrounding areas in the Franklin ★ Crystals frequently twin; a famous marble. Its chemical formula is twinning habit is the Japanese twin, Ca(Mn,Zn,Fe)Si2O6. where two crystals contact at a 90° URALITE – Pseudomorph of angle. Actinolite after any mineral of the ★ Quartz crystals may also contain a pyroxene group, especially Augite. scepter growth, where the top of a crystal bulges out from the rest of USES OF AUGITE the crystal, and may also from as  phantom growth, where one crystal forms over another, leaving a ghosted form inside. ★ The crystal structure of Quartz is very complicated. Its crystals form hexagonal prisms with modified crystal faces. TRANSPARENCY: Transparent to opaque SPECIFIC GRAVITY: LUSTER: Vitreous. Transparent, colorless Quartz crystals from a few distinct localities may be adamantine. CLEAVAGE: Indiscernible. Seldom exhibits parting. FRACTURE: Conchoidal TENACITY: Brittle OTHER ID MARKS: 1) Some specimens fluoresce, especially white and green. 2) Triboluminescent. 3) Piezoelectric. COMPLEX TESTS: Dissolves in hydrofluoric acid IN GROUP: Silicates; Tectosilicates; Silica Group STRIKING FEATURES: Hardness, crystal forms, striations on crystal faces, and frequent appearance of conchoidal fractures on crystal faces. ENVIRONMENT: Quartz occurs in almost every single mineral environment. ROCK TYPE: Igneous, Sedimentary, Metamorphic POPULARITY (1-4): 1 PREVALENCE (1-3):1 DEMAND (1-3): 1  HORNBLENDE AS A ROCK-FORMING MINERAL ★ Hornblende is an important constituent in acidic and intermediate igneous and metamorphic rocks such as gneiss and schist. ★ Amphibolite: rocks mainly composed of amphibole mineral ★ Lamprophyre: an igneous rock mainly composed of amphibole and biotite with feldspar ground mass PHYSICAL PROPERTIES OF HORNBLENDE CHEMICAL CLASSIFICATION: Silicate COLOR: Usually black, dark-green, dark-brown USES OF QUARTZ STREAK: White, colorless – (brittle, often Sand, composed of tiny Quartz leaves cleavage debris behind instead of a pebbles, is the primary ingredient for streak) the manufacture of glass. LUSTER: Vitreous used as oscillators in radios, DIAPHANEITY: Translucent to nearly watches, and pressure gauges, and opaque in the study of optics CLEAVAGE: Two directions intersecting at used as an abrasive for 124 and 56 degrees Mohs sandblasting, grinding glass, and HARDNESS: 5 to 6 cutting soft stones. SPECIFIC GRAVITY: 2.9 to 3.5 (varies Used as an important silicon depending upon composition) semiconductor DIAGNOSTIC PROPERTIES: Cleavage, essential to the gem trade color, elongate habit Some wear small colorless Quartz CHEMICAL COMPOSITION: crystals as pendants for good luck (Ca,Na)2–3(Mg,Fe,Al)5(Al,Si)8O22(OH,F)2 CRYSTAL SYSTEM: Very little industrial use USES OF HORNBLENDE HORNBLENDE used as a mineral specimen ➔ used to describe Ferrohornblende It is the most abundant mineral in a and Magnesio-hornblende, but used rock known as amphibolite which for ALL calcium aluminum has a large number of uses. amphiboles used for highway construction and ➔ used to describe any dark, opaque as railroad ballast. amphibole mineral use as dimension stone. ➔ named after the German term horn, highest quality pieces are cut, referring to its color and blenden: polished, and sold under the name meaning "deceiver" "black granite" for use as building ➔ major constituent of the earth and is facing, floor tiles, countertops, and extremely common other architectural uses. ➔ a rock-forming mineral, and it even used to estimate the depth of constitutes its own rock type known crystallization of plutonic rocks. as Horneblendite: a dark rock useful in understanding the formed mostly from Hornblende. crystallization of magma and also ➔ its typical dark color and opacity are useful for mineral exploration. usually caused by iron in its structure BIOTITE  ➔ a very common form of mica ➔ named in honor Jean Baptiste Biot ★ Crystals are in thick flakes, (1774 - 1862), a French physicist, micaceous masses and groupings, mathematician, and astronomer who and in tabular, foliated, flaky, and researched the mica minerals for scalyforms. their optical properties. ★ may also be elongated with one ➔ its presence is usually lacking in dimension flat, or stubby triangular collections except for it being an or hexagonally shaped accessory mineral to other minerals ★ prismatic barrel-shaped or tapered ➔ can come in enormous crystal pyramidshaped crystals sheets and weigh several hundred pounds or in thin sheets TRANSPARENCY: Translucent to opaque. ➔ very hard to clean because if SPECIFIC GRAVITY: 2.8 – 3.4 washed it will absorb water internally LUSTER: Pearly and start to break apart; use dry CLEAVAGE: 1, 1 electric toothbrush FRACTURE: Uneven TENACITY: Sectile, elastic ★ In 1998, the IMA removed the status OTHER ID MARKS :Tendency for small of Biotite as an individual mineral pieces or flakes or peel off. species, and instead declared it as a IN GROUP: Silicates; Phyllosilicates; Mica group name for the following Group individual members: Phlogopite, STRIKING FEATURES: Flaky habit, Annite, Siderophyllite, and crystals, sectility, and mode of occurence Eastonite. ENVIRONMENT: a common rock-forming mineral, and is especially noted in PHYSICAL PROPERTIES OF BIOTITE metamorphic rocks. It is also found in igneous rock and the primary mica in rare CHEMICAL FORMULA: The classic earth pegmatites formula for Biotite is: ROCK TYPE: Igneous, Metamorphic K(Mg,Fe2+3)(Al,Fe3+)Si3O10(OH,F)2 POPULARITY (1-4): 2 PREVALENCE (1-3): 1 The group formula including all member DEMAND (1-3): 2 minerals: K(Mg,Fe2+)3(Al,Fe3+)[(Al,Si)3O10](OH,F)2 VARIETIES MANGANOPHYLLITE- manganese-rich Individual members are: Phlogopite: KMg3AlSi3O10)(F,OH)2 Siderophyllite: KFe2+2Al(AlSi2O10)(OH)2 Eastonite: KMg2Al(AlSi2O10)(OH)2 Annite: KFe2+3AlSi3O10(OH)2 Fluorannite: KFe2+3AlSi3O10)F2 Tetraferriannite:K(Fe2+3Mg)(Fe3+,Al)Si3O 10)(OH)2 MUSCOVITE most common mineral of the mica COMPOSITION: Basic fluoro potassium, family magnesium, iron aluminum silicate important rock-forming mineral COLOR: Black, dark brown, dark green, present in igneous, reddish black. Individual group member metamorphic, and sedimentary minerals such as Phlogopite and Eastonite rocks. can be in lighter colors. Sheets are nearly colorless but may STREAK: White have slight tints of brown, yellow, green, or rose. HARDNESS: 2.5 – 3 1700s, it was mined for this use from CRYSTAL SYSTEM: Monoclinic pegmatites in the area around Moscow, Russia. These panes were called “muscovy glass” and that term is thought to have inspired the mineral name “muscovite”. CRYSTAL FORMS AND AGGREGATES: PHYSICAL PROPERTIES OF aluminum, the mineral becomes MUSCOVITE green, known as "fuchsite," which is often found in metamorphic rocks of CHEMICAL FORMULA: KAl3Si3O10(OH)2 the greenschist facies. If fuchsite is COMPOSITION: Basic potassium aluminum abundant enough to color the rock silicate, sometimes with some chromium or distinctly green, it is referred to as manganese replacing the aluminum "verdite." VARIABLE FORMULA: USES OF GROUND MICA K(Al,Cr,Mn)3Si3O10(OH)2 Muscovite is a poor conductor of COLOR: Colorless, white, beige, yellow, heat and electricity. brown, gray, green, pink, purple, red, black; Used as an insulator in electrical occasionally multicolored products and semiconductors. STREAK: Colorless Incorporated in the production of HARDNESS: 2 – 2.5 automotive tires and in cosmetics. Historically used for oven windows CRYSTAL SYSTEM: Monoclinic ("isinglass") due to high-temperature CRYSTAL FORMS AND AGGREGATES: resistance. Muscovite crystals vary in form, including thick flakes, micaceous masses, and tabular VARIETIES OF MUSCOVITE or scaly shapes. They can be elongated, ALURGITE – manganese-rich, pink triangular, or hexagonal, and form unique to red variety of Muscovite. aggregates like dense bladed crystals, FUCHSITE – dark green, chromium-rich variety of Muscovite. rosettes, and globular masses. Muscovite Named in honor of German may also exhibit pseudomorphs, taking on professor and mineralogist Johann the shapes of other minerals. Nepomuk von Fuchs (1774 – 1856). SPECIFIC GRAVITY: 2.7– 3.0 MARIPOSITE – Green form of LUSTER: Pearly Muscovite mica, found in Mariposa CLEAVAGE: 1, 1 and Tuolumne County, California. FRACTURE:Uneven Occurs in metamorphosed dolomite and quartz, typically in veins or as a TENACITY: Sectile, Elastic base material. OTHER ID MARKS: Tendency for small - Combination of green mica and pieces or flakes or peel off. surrounding materials creates the IN GROUP: Silicates; Phyllosilicates; Mica rock also called Mariposite. Group -Sometimes utilized as an STRIKING FEATURES: Flaky habit, ornamental stone. SCHERNIKITE – a light pink form of crystals, sectility, and mode of occurrence Muscovite. ENVIRONMENT: Muscovite is a very SERICITE – a fine-grained form of common rock-forming mineral and is mica, usually Muscovite, that is important. Its noted especially in granite somewhat silky in appearance. pegmatites, in contact metamorphic rocks, STAR MUSCOVITE – describes in metamorphic schists, and in hydrothermal twinned Muscovite crystals in veins. Important muscovite deposits where pointed star- shaped sections large significant crystals occur are almost CALCITE exclusively from granite pegmatites. A rock-forming mineral with the ROCK TYPE: Igneous, Metamorphic chemical formula CaCO3. POPULARITY (1-4): 1 Extremely common and found PREVALENCE (1-3): 1 worldwide in sedimentary, DEMAND (1-3): 1 metamorphic, and igneous rocks. Considered a "ubiquitous mineral," essential in the formation of limestone and marble. Acts as a significant carbon reservoir in the Earth's crust. CHEMICAL COMPOSITION Widely used in construction, Muscovite is a potassium-rich mica abrasives, agricultural treatments, with the following generalized pigments, pharmaceuticals, and composition: KAl2(AlSi3O10’)(OH)2 more. In muscovite, potassium can be Has more applications than nearly replaced by ions like sodium, any other mineral. rubidium, or cesium, while aluminum may be substituted by magnesium, iron, lithium, chromium, or CALCITE AS LIMESTONE AND MARBLE vanadium. When chromium replaces  A sedimentary rock primarily TENACITY: Brittle composed of calcite. OTHER ID MARKS: Forms through chemical Commonly fluorescent; specimens from precipitation of calcium carbonate different localities fluoresce different colors. and the transformation of biological Some calcite is also phosphorescent. debris (shells, coral, feces, algae) Transparent crystals exhibit strong double during diagenesis. refraction. Can also form from calcium May be thermoluminescent. carbonate precipitation in caves. COMPLEX TESTS: A metamorphic rock that originates Effervescent in hydrochloric acid and most from limestone under heat and other acids. pressure. Calcite that doesn’t fluoresce usually Broken marble typically shows clear becomes fluorescent upon heating. cleavage faces of calcite. IN GROUP: Carbonates; Calcite Group The size of calcite crystals in marble STRIKING FEATURES: Hardness, increases with the degree of cleavage, fluorescence, and effervescence metamorphism. with hydrochloric acid. ENVIRONMENT: Calcite is a constituent of USES OF CALCITE all mineral environment, including The construction industry sedimentary, igneous, and metamorphic. predominantly uses calcite as ROCK TYPE: Igneous,cSedimentary, limestone and marble. Metamorphic These rocks have served as POPULARITY (1-4): 1 dimension stones and mortar for PREVALENCE(1-3): 1 thousands of years, notably in the DEMAND (1-3): 1 pyramids of Egypt and Latin America. Rough and polished limestone and marble are essential in prestige architecture. Calcite is crucial for producing cement and concrete, which are easily mixed and transported. Concrete is utilized for buildings, VARIETIES OF CALCITE highways, bridges, walls, and AGARIC MINERAL – crumbly white various structures. calcite found on cavern floors near stalagmites and stalactites. PHYSICAL PROPERTIES OF CALCITE ANTHRACONITE – dark gray to CHEMICAL FORMULA: CaCO3 black variety of calcite with abitumen COMPOSITION: Calcium carbonate, coating or inclusions. sometimes with impurities of iron, COBALTOCALCITE – refers to an magnesium, or manganese, and intermediary mineral between occasionally zinc and cobalt. Calcite and Sphaerocobaltite in a VARIABLE FORMULA: solid solution (Ca,Fe,Mg,Mn,Zn,Co)CO3 DOGTOOTH CALCITE – calcite in COLOR: Colorless, white, yellow, brown, groupings of thick and pointy orange, pink, red, purple, blue, green, gray, scalenohedral crystals. black, may also be multicolored or banded. FLOWSTONE – calcite formed by STREAK: White mineral-rich water that deposits the HARDNESS: 3 dissolved mineral on the walls of CRYSTAL SYSTEM: Hexagonal caverns and cliffs, forming a smooth CRYSTAL FORMS AND AGGREGATES: and humpy growth. Occurs in a great variety of shapes, with the ICELAND SPAR – large, most common forms asrhombohedral and transparent, colorless to lightly scalenohedralcrystals. Crystals may be colored, rhombohedral variety of tabular, acicular, prismatic, flaky, and Calcite. Double refraction is needle-like. May occur as bundles of especially noted in Iceland Spar scalenohedrons, inter grown crystals. rhombohedrons, hair-like masses of acicular ONYX MARBLE – travertine or tufa crystals, grainy, stalactitic, fibrous, massive, in the mineral form of Aragonite or and earthy. Scalenohedral twinning is Calcite that exhibits color banding. common. SALMON CALCITE – orange- red, TRANSPARENCY: Transparent to opaque “salmon” colored variety of Calcite SPECIFIC GRAVITY: 2.7 that is usually opaque. LUSTER: Vitreous SAND CALCITE – calcite that CLEAVAGE: 1, 3 – rhombohedal trapped particles of sand in its FRACTURE: Conchoidal. Rarely observed interior when it formed. due to the perfect cleavage  STALACTITE – icicle-like mineral Physical Properties: formation found on the roof of Luster: Vitreous. caverns, created when mineral-rich Diaphaneity: Transparent to water drips down and the dissolved translucent. mineral accumulates into the Tenacity: Brittle. icicle-like formation. Cleavage: None. STALAGMITE – tall, domed mineral Forms: Can be found as individual formation found on the roof of crystals, stream-worn pebbles, caverns, created when mineral-rich granular aggregates, and massive water drips down and the dissolved occurrences. mineral accumulates into the Characteristics: Vary in chemical icicle-like formation. composition, specific gravity, TRAVERTINE – mounds of calcium hardness, and color. carbonate formed from hot springs that contain calcium-rich water that bubbles up to the earth and cools down, and its capability to hold calcium is reduced. The water eliminates the calcium, the calcium forms a growing mound of calcium carbonate, which is porous. Travertine is usually Aragonite, although it may also be calcite TUFA – aragonite formed from precipitating water that traps in organic matter, such as leaves, twigs, and moss. Also, calcareous mounds formed from deposition of hot springs that trap in organic matter. GARNET a large group of related, rock-forming minerals rather than a single mineral. Members of the garnet group are isomorphous and can form intermediary minerals between each other. Different garnet types may intergrow within a single crystal. Variations in physical properties among garnets are minimal, making some members indistinguishable without x-ray analysis. The common Garnets can be divided into two subgroups: Group 1: Garnets containing aluminum (Al) as their second element. ❖ These include Pyrope, Almandine, and Spessartine. ("Pyralspite") Group 2: Garnets containing calcium (Ca) as their first element. ❖ These include Uvarovite, Grossular, and Andradite. ("Ugrandite") there are variety of different types of The members of each group freely garnet, and each has a different intermingle among one another. chemical composition. There are solid solution series between most of GARNET PHYSICAL AND CHEMICAL the garnet minerals. This wide PROPERTIES variation in chemistry determines Common Garnet Minerals: many of their physical properties. As almandine, pyrope, spessartine, an example, the calcium garnets andradite, grossular, and uvarovite. generally have a lower specific  gravity, a lower hardness and are used as gemstone for thousands of typically green in color. In contrast, years. the iron and manganese garnets used as an indicator mineral during have a higher specific gravity, a mineral exploration and geologic greater hardness and are typically assessments. red in color. In the past 150, it has seen many additional uses of garnet in the HOW DOES GARNET FORM? United States. GARNET I N METAMORPHIC ROCKS Most garnets form at convergent plate boundaries through regional metamorphism, particularly from shale. Heat and pressure break chemical bonds, causing minerals to recrystallize into stable structures. The aluminum garnet that typically forms in this metamorphic environment. Garnets start as tiny grains, enlarging over time and displacing surrounding rock materials, often resulting in high inclusion of other minerals. Microscopic view shows garnet grains growing within a schist matrix, incorporating mineral grains. Lesson 3: PROPERTIES, PROCESS Form when argillaceous limestone is OF FORMATION OF ALL MINERALS altered into marble via contact metamorphism near igneous intrusions (e.g., andradite, grossular, FORMATION OF MINERALS uvarovite). Time Notable green garnets include tsavorite (bright green grossular) - one of the most important factors and demantoid (golden-green because it takes time for atoms to andradite), both highly valued in the become ordered. (limited time = gem trade. remained very small grains) GARNET IN IGNEOUS ROCKS Garnet is often found as an Presence of water accessory mineral in igneous rocks, - enhances the mobility of ions and particularly granite. can lead to the formation of larger Commonly recognized as dark red crystals in granite, often used in crystals over shorter time periods. countertops. An orange garnet found as crystals Magma – molten rock in granite pegmatites. *Most of the minerals that make up the A red garnet that originates from peridotite brought to the surface rocks around us formed through the during deep-source volcanic cooling of magma. eruptions. Garnet is also present in basaltic Rapid cooling process lava flows. - minerals won’t have time to become GARNET IN SEDIMENTARY ROCKS AND ordered SEDIMENTS - the resulting rock will be fine-grained Garnets are relatively durable minerals. They accumulate in soils and Slow cooling process sediments from the weathering and - higher degree of ordering erosion of garnet-bearing rocks. - large crystals Often targeted in mining operations due to their easy extraction from sediment and soil through Volcanic glass mechanical processing. - In some cases, the texture will be glassy, which means that no crystals USES OF GARNET at all form - Not composed of minerals - Ex. Sulphur – distinctive and unique - May crystallize into various silicate yellow, hematite – deep dull red, minerals over time black, shiny metallic 2. Streak - color of the powder produced when Minerals can also form in several it is dragged across an un-weathered ways: surface (unglazed porcelain) Precipitation – from aqueous solution 3. Lustre Precipitation – from gaseous - Good diagnostic property, minerals emanations will always appear metallic or Metamorphism – formation of new non-metallic minerals directly from the elements - The way light reflects off the surface within existing minerals under of a minerals conditions of elevated temperature - Degree to which it penetrates into and pressure the interior Weathering – during which minerals - Key distinction: metallic and unstable at Earth’s surface may be non-metallic lustres altered to other minerals - Light does not pass through metals Organic formation – formation of makes it look metallic minerals within shells (primarily - Glassy – non-metallic has a shiny, calcite) and teeth and bones reflective ruface (primarily apatite) by organisms - Earthy – dull and non-reflective (these organically formed minerals are still called minerals because they 4. Hardness can also form inorganically) - One of the most important diagnostic properties of minerals Opal - Mohs Hardness Scale - used as a - mineraloid, because although it has convenient way to help identify all of the other properties of a minerals mineral, it does not have a specific - Friedrich Mohs, German mineralogist structure. - Reference materials that geologist use to measure the Pearl hardness - not a mineral § Fingernail - can only be produced by organic § Piece of copper wire processes § Knife blade § Piece of window glass Minerals are universal § Hardened steel file - crystal on Earth will be the same on § Porcelain streak plate the other planets 5. Crystal habit - Reflection of how minerals grow - Not so useful diagnostic feature because beautiful well-formed MINERALS PROPERTIES crystals are rare 1. Colour - Regular arrangement of the - One of our key ways of identifying molecules that make up the mineral objects - Minerals will form in distinctive - Some minerals have particularly crystal shapes if they are not distinctive colours, some do not crowded out by other pre-existing - Unreliable minerals - Ex. Quartz – six-sided prisms with - Calcite is soluble in dilute acid and pointed ends, happens when it will give off bubbles of carbon crystallizes from a hot water solution dioxide within a cavity in an existing rock - Magnetite is magnetic - Ex. Pyrite – cubic crystals or 12-faced crystals (aka dodecahedra) Some terms that are used to describe habit: Lesson 4: Coal and Petroleum § Bladed § Botryoidal (grape-like) Coal § Dendritic (branched) · Coal is a hard, solid fossil fuel § Drusy (an encrustation of minerals) primarily composed of carbon, along with § Equant (similar in all dimensions) hydrogen, sulfur, oxygen, and nitrogen. § Fibrous § Platy · It is classified as a sedimentary rock. § Prismatic (long and thin) As a major energy source, coal is widely § Stubby used for electricity generation and heating. 6. Cleavage and fracture · Coal are fossil fuel and are the altered - Reflection of how minerals break remains of ancient vegetation - Most important diagnostic features of many minerals · energy we get from coal today comes - Often the most difficult to from energy that plants taken into the sun. understand and identify Peat or bogs - Cleavage - what we see when a mineral breaks along a specific plane · formed from the remains of plants such or planes as those of the late Carboniferous period - Fracture – irregular break or Paleozoic era. - Quartz – have no cleavage because it has equally strong Si-O bonds in Formation of coals all directions As the trees and plants died, they drop to - Feldspar – has two cleavages at 90 the bottom of the bog of oceans to form degrees to each other layers of spongy materials called peat. Difficulties with recognizing cleavage Over a many years, peat was covered by - Visible only in individual crystals sand, the clay turned into sedimentary - Most rocks have small crystals and rocks. More rock stack on top of old rock it’s very difficult to see the cleavage and began to press on the peat. It was within a small crystal press and turned into fossil fuels. Coke 7. Density - Measure of the mass of a mineral · It is virtually pure form of carbon. It is a per unit volume porous, black and the same as the coal. It - Useful diagnostic tool has high percentage of the carbon and low - Quartz, feldspar, calcite, amphibole, in impurities mica – have “average density” (2.6 – · Coal can be heated very hot in a place 3 g/cm^3) where there is no oxygen or what we called - Metallic minerals, pyrite, hematite, the airless space to produce coke and magnetite – 5 g/cm^3 - Limitation: cannot assess minerals · Coke can be used in smelting to that are a small part of a rock with reduce metals from their minerals. It is used other minerals in it in producing steel and in the extraction of many types of metals. Other properties Coal Tar · Coal tar is a highly viscous kind of liquid · softest and the lowest in carbon but high and is brown-black in color. It is a inconstant in hydrogen and oxygen content. mixture of many substances BITUMINOUS COAL · It is used to in producing of many product like synthetic dyes, explosive, · dense rock, black but sometimes dark perfumes, roofing materials, drugs, plastics brown and are greatly used in industry as a and many more source of heat energy. · It is almost about 20 years ago, when · in between of anthracite and lignite coal tar was used as a binding material in making of the road SUB-BITUMINOUS COAL Coal Gas · used as fuel for steam-electric power generation. · The coal gas is one of the by-products in processing of the coke. A STEAM COAL flammable gaseous product obtained by · used as a fuel for steam locomotives. heating coal in the absence of air · small steam coal are used as a fuel for Uses of coal gas domestic water heating Heating: Coal gas was historically ANTHRACITE used for residential heating and cooking. · also known as hard coal and more Lighting: It was commonly used carbon in gas lamps before electricity · harder, glossy, black coal became widespread. Industrial Fuel: Used in various · longer burning, and used mainly for industrial processes for heating residential and commercial space heating. and as a fuel source. Chemical Production: Coal gas PETROLEUM serves as a raw material for producing chemicals like · Petroleum is a natural liquid found ammonia and methanol. below the Earth’s surface that can be Power Generation: In some refined into fuel. applications, it can be used to · Petroleum is a fossil fuel generate electricity. · created by the decomposition of Types of Coal organic matter over many years. PEAT · formed in sedimentary rock under in the intense heat and pressure. · fibrous, soft, and spongy substance which plant remains are easily Uses of petroleum recognizable. They contain a large amount of water and must be dry before · used as fuel to power vehicles, heating use. units, and machines of all sorts, and also being converted into plastics and other LIGNITE materials. · formed when peat are subjected to · the petroleum industry is extremely increased vertical pressure from powerful and it is a major influence on world accumulating sediments politics and the global economy. · dirtiest coal and are used as fuel for Formation of Petroleum electric power generation. · Small sea plants and sea animals died ü sour crude contains the sulfur and sulfuric and are buried on the sea or ocean floor for compounds, which can make the fuel less many years valuable. · the died plants and animals in the ocean The petroleum industry is divided were covered by the layers of sand and silt. into three key segments: · the remains were buried extending far Upstream: Exploration, downwards extraction, and production of · because of the high pressure and crude oil. temperature on water the dead organisms Midstream: Storage, were transformed to petroleum. transportation, and processing of crude oil and refined products. v petroleum is also known as the fossil Downstream: Refining and fuels because it is product of the dead distribution of finished products, organisms such as gasoline, to consumers. Refining of Petroleum · Petroleum refinery is the place Extraction of Petroleum where the refining process of the petroleum is performed. Asphalt, which is used to pave highways, is also made from petroleum. Vehicles which drive on highways are made on materials that derived from petroleum and run on Petroleum Products And Their Uses fuels refined from petroleum. Petrol - fuels the motor car, solvent in · Petroleum is most frequently related with dry cleaning, and aeronautics. crude oil and the wells dug into the ground to bring that liquid to the surface. Diesel - can fuels the heavy vehicle, like trucks, rail engine and small vehicle like · can vary in color, from relatively vans, jeep, jet aircraft, small generators, transparent to dark brown or black. and many more. o Heavier oils are usually the darkest in Bitumen - is used to make roads, paints color. and many more. · Petroleum contains various types of hydrocarbons, and natural gas is commonly Kerosene - it fuels gas stoves, lamps, found dissolved in the liquid in essential jet aircraft and many more. amounts. Parrafin - can use in producing an · Hydrocarbons can be processed in ointment, cosmetics, and even candles, refineries into different types of fuels. and many more. · Hydrocarbon molecules in petroleum Lubricating oil - is used as a lubricants include asphalt, paraffin, and naphthene. in engines. ü The more dense of the petroleum the Liquid Petroleum Gas - it fuels vehicle, more difficult it is to process and the less and fuel in household. valuable it is. ü light crude is the easiest to refine and are generally considered as the most valuable, while the viscosity of the heavy crude can make it more expensive to refine  ➔ iron ore ➔ manganese ➔ copper ➔ thorium ➔ uranium ➔ mica ➔ coal (including coking coal) Madhya Pradesh holds good reserves of: ➔ iron and manganese ores ➔ coal ➔ limestone ➔ bauxite Madras, Mysore, Hyderabad, Kerala, Rajasthan, and other states have various mineral deposits such as: ➔ gold, iron, mica, ilmenite, zircon, and more. Notable Mineral Reserves by Region: Bihar and Orissa: ➔ Large reserves of iron ore (over 8,000 million tons) and mica (50% of global supply). Kerala: ➔ Rich in heavy minerals like ilmenite, monazite, zircon, Lesson 5:THEIR OCCURENCE AND and garnet. ORIGIN IN INDIA Mysore: ➔ All of India’s gold production, India’s Mineral Wealth: with significant reserves of iron and chrome-ore. India has a considerable range of Rajasthan: economically important minerals, ➔ A latecomer in India's mineral despite limited resources in some production, but now areas. becoming a productive Notable minerals with substantial center. reserves include iron ore, ➔ Emerging as a producer of aluminum ore, titanium ore, and copper, lead, zinc, mica, mica. and precious stones like aquamarine and emerald. Geophysical Methods: Uttar Pradesh and Eastern Punjab: Modern techniques such as ➔ Have been relatively electrical, magnetic, gravimetric, unproductive, with little and seismic methods offer contribution to India’s mineral possibilities for discovering hidden statistics. deposits of minerals like petroleum, West Bengal: coal, natural gas, and metallic ➔ Confined mostly to coal lodes. (annual capacity of about 16 Uneven Distribution of Minerals: million tons) and iron ore. Himalayan Region: Vast northern alluvial plains lack ➔ Kashmir (south of the Great significant mineral deposits. Himalayan Axis): Archaean terrain of Bihar and has proven reserves of coal Orissa is mineral-rich, containing (some anthracitic), major reserves of:  aluminum ore, sapphires, 574 mines focus on coal. and minor industrial minerals. 700 mines work on metallic ➔ Kumaon and Sikkim: minerals. Large reserves of magnesite 1725 mines extract non-metallic and partly known copper minerals. deposits. ➔ Other areas of the Natural resources (water, forests, energy, Himalayan region remain minerals, land, and human resources) are largely unexplored for vital to India’s economy. economic minerals. Sikkim and Bhutan: *Among the resources, minerals are the ➔ Similar to the rest of the major contributors of the national economy. Himalayan region, with India is the country, much dependant on the limited exploration for available natural resources for its economy. minerals. Nepal: ➔ Fairly mineralized terrain. ➔ Known for occurrences of cobalt, nickel, and copper-ore, though geological exploration is not yet comprehensive. Mineral Variety in India: India has 86 economically important minerals: ○ 10 metallic minerals. ○ 46 non-metallic minerals (industrial). ○ 3 atomic minerals. ○ 23 minor minerals (including building materials). ○ 4 fuel minerals. Two Vital Resources of India Metallic and non-metalic mineral resources Mineral fuels Six core industries controlling the national economy of India (supported by mining sector): 1. Crude oil 2. Petroleum 3. Coal 4. Electricity 5. Cement 6. Finish carbon steel Mining Operations: 2999 mines operate on various minerals.