Minerals Lecture Notes PDF
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Saint Catherine of Siena Academy, Inc.
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This document provides lecture notes on minerals, discussing their properties, such as color and luster, and their uses. It covers various types of minerals and their characteristics, including their chemical composition and crystal forms.
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MINERALS LECTURE NOTES MINERAL is an element or inorganic compound that occurs naturally in the earth’s crust as a crystalline solid or one that has regular repea@ng internal arrangement of its atoms. Proper@es of Mine...
MINERALS LECTURE NOTES MINERAL is an element or inorganic compound that occurs naturally in the earth’s crust as a crystalline solid or one that has regular repea@ng internal arrangement of its atoms. Proper@es of Minerals: COLOR ❖ absorp@on or lack of visible light ❖ appearance in reflected/transmiJed light Malachite: gemstones, sculpture, pigment, used to be an ore of copper Azurite: Ancient people used it as an ore of copper, as a pigment, as a gemstone, and as an ornamental stone. It is s@ll used for all of these purposes today. Is color a very reliable property to be used to dis@nguish one mineral over another? The first industrial use of garnet was as an abrasive Crushed garnet granules are used to make garnet sandpaper. FACTORS that may change color of mineral: Presence chemical impurity, atomic anomalies, exposure to heat, radia@on Proper@es of Minerals: LUSTER ❖ Luster-how minerals reflect light off its surface Metallic- opaque and resplendent shine (newly polished metal) Galena (PbS)- ore of lead Non-metallic Adaman@ne- Diamond Vitreous (broken glass) – Quartz ***Adaman5ne minerals possess a superla5ve luster, which is most notably seen in diamond. Such minerals are transparent or translucent, and have a high refrac@ve index -slow light travels, bent light Vitreous- white light is reflected back, glassy, transparent (low refrac@ve) reflec@ve-bouncing of light, refrac@ve-bending of light ❖ Luster- how minerals reflect light Non-metallic Pearly- Talc Silky - Gypsum Dull/Earthy-Hema@te Waxy/ Resinous- Jade Pearly: Light is broken into colors; looks like oil on water Silky: cloth like, Wallboard and construc@on plaster are the primary industrial uses of gypsum in the United States. Plaster of paris, quick-se`ng gypsum plaster consis@ng of a fine white powder (calcium sulfate hemihydrate), which hardens when moistened and allowed to dry. It is commonly used to precast and hold parts of ornamental plasterwork placed on ceilings and cornices. It is also used in medicine to make plaster casts to immobilize broken bones while they heal, earthy luster- poor reflec@vity-coarse, porous Resinous- candle like, sob shine, maJe, greasy luster Proper@es of Minerals: Streak ❖ color of powder the mineral leaves when you rub it on an unglazed porcelain plate ❖ not always the same with the mineral’s color metallic - streak dark as mineral nonmetallic - streak colorless to light Proper@es of Minerals: Crystal form or Habit ❖ visible expression of a mineral’s internal arrangement of atoms *****The number of lines that are created when a mineral is split will be the number of cleavage lines. Muscovite is the most common mineral of the mica family. The ability of muscovite to split into thin transparent sheets - some@mes up to several feet across - gave it an early use as window panes. Used in the manufacturing of paint, joint compound, plas@cs rubber, asphalt roofing, cosme@cs, drilling mud. Joint compound (also known as drywall compound or Mas@c) is a white powder of primarily gypsum dust mixed with water to form a mud the consistency of cake fros@ng, which is used with paper or fiber joint tape to seal joints between sheets of drywall to create a seamless base for paint on interior walls. Dis5nc5ve Proper5es of Minerals Talc- feels soapy Graphite- feels greasy Magne@te - magne@c Calcite- double refrac@on, fizz in HCl Mineral Groups (Chemical Composi@on) ****The most stable basis for classifica@on of minerals is based on their chemical composi@ons. Na5ve element minerals are those elements that occur in nature in uncombined form with a dis@nct mineral structure. The chemical basis for classifying minerals --ANION SILICATES- most common on earth’s crust, Igneous rocks OXIDES- industrial purposes (magne@te-iron, ru@le-@tanium) SULFATES- metal salts, therapeu@c baths, detergents, foaming agents and emulsifiers SULFIDE-sulfur(medicinal) CARBONATE-cements, ceramic glazes HALIDE- cleaning materials
