Stone Info_ Lapi Lazuli, Turquoise & More PDF

****** Lapis Lazuli, Turquoise, & Other Opaques Gems ******** LARGEST CONSUMERS : Lapis Lazuli: not a high-priced gemstone, used incommercial jewelry & cutting-edge designer jewelry Turquoise: top-quality turquoise with no matrix command the highest prices, spiderweb matrix turquoise comes in secon...

****** Lapis Lazuli, Turquoise, & Other Opaques Gems ******** LARGEST CONSUMERS : Lapis Lazuli: not a high-priced gemstone, used incommercial jewelry & cutting-edge designer jewelry Turquoise: top-quality turquoise with no matrix command the highest prices, spiderweb matrix turquoise comes in second, The largest and most consistent market is the Amercian Southwest, commercial is cheap mass produced are sold here and high quality designed by Native American artisans COLOR/HUE RANGE/VALUE: Lapis Lazuli: semitranslucent to opaque, of fair toughness, with a waxy to vitreous luster, finest color is violetish blue, medium to dark in tone, and highly saturated with no visible calicite but might have fleck of gold colored pyrite, it also comes in deep violet blue and royal blue to light blue to turquoise blue to a greenish blue hues Lapis trade grades are based on color: (country names used doesn't confirm place of origin) -Afghan—Intense, uniform, medium-dark, slightly violetish blue. Contains little or no pyrite, and no calcite -Russian or Siberian—Various tones and intensities of blue. Contains pyrite and might contain some calcite -Chilean—Often tinged or spotted with green, with obvious calcite matrix Turquoise: semitranslucent to opaque,waxy luster , Amercian & Mexican is light blue, or greenish blue to bluish green, while Egyptian turquoise is greenish blue to yellowish green, even distribution of color is preferred Malachite: vivid bluish green to green hue, silky to vitreous luster, and distinctive banding Azurite: his mineral species is a dark blue to violetish blue, usually semitranslucent to opaque with a vitreous to waxy luster Azurite-malachite: a blend of the two gems with bands of oceanic blue and green give the gem’s surface the look of swirling surf Fluorite: comes in many colors, but "Blue John"is most popular with bluish violet to purple curved or angular bands appear on a reddish to colorless background and vitreous luster Sugilite: rich red-purple to bluish purple hue, semitransparent to opaque with a waxy to vitreous luster, most familiar in dark hues, it’s occasionally light in tone, almost pink Charoite: luscious violet color that forms the background for swirls, veins, and patches of black, gray, white, and brownish orange with vitreous to waxy luster Onyx Marble: fairly subdued, with bands of grays and whites Rhodochrosite: fine quality transparent pink to dark red that resembles ruby’s color, Translucent and opaque aggregate specimens are plentiful, and they’re usually pink with soft-edged bands of white, gray, brown, or yellow, typically faceted Rhodonite: rosy hue: a warm orange-pink to brownish or purplish red with black veins or patches, rarely transparent, generally opaque, sometimes called "pink marble", Hematite: an opaque dark gray to black gem, sometimes called “black diamond", Pyrite: opaque material with a metallic brassy yellow appearance, often mistaken as fallen meteorite, "fools gold", it can be silvery gray (like hematite) , "marcasite" is a trade Unakite: granite aggregate consisting of quartz, pink feldspar, and green epidotered, pink, and green. The rock is tumbled or fashioned into cabochons. Sodalite: royal blue,The deep blue color is occasionally flecked with spots of bright red, pink, or orange, semitransparent to opaque VARIETY/SPECIES/GROUP: Fluorite: variety " Blue John" Onyx Marble: a variety of calcite CHEMICAL COMPOSTION: Lapis Lazuli: aggregate of lazurite, calcite, and pyrite (Sometimes contains one or more of the following: diopside, amphibole, feldspar, and mica) Trace element lazurite produces royal blue lapis, while the mineral afghanite creates a pale blue shade Turquoise: hydrated copper and aluminum phosphate, trace elements of more iron make greenish blue, bluer shades have greater amounts of copper, often a byproduct of copper mining Malachite: trace elements of copper Azurite: trace elements of copper Sugilite: trace elements of manganese, mineral sugilite and other materials Rhodochrosite: Trace element is manganese, clusters within a matrix of quartz and the mineral tetrahedrite FORMING SOURCE: Lapis Lazuli: frequently contains whitish calcite matrix— host rock are flecks or veins of glinting yellow pyrite, or both Turquoise: limonite or sandstone, Limonite matrix creates dark brown markings in turquoise CRYSTAL STRUCTURE: Turquoise: cryptocrystalline aggregate of microscopic crystals POSSIBLE PHENOMENA: n/a COMMON CUTS: Lapis Lazuli: cabochons, beads, inlays, and tablets, free-form and nature-themed sculptures, historically used as carving material for things like game boards, bowls, dagger handles, hair combs, and amulets Turquoise: cabochon, round or oblong beads, small flat piece inlays, traditional jewelry of Native American ( Pueblo, Hopi, Zuni, and Navajo), also carved jewelry and art objects like tailsmans Malachite: inlays and carvings, and also in bead necklaces and other jewelry Sugilite: Typically seen in cabochons and beads as well as carvings Charoite: most often made into cabochons, beads, and carving Onyx Marble: Bookends and other carvings of onyx marble are common and sold in the US Rhodobite: carved or cabochon Hematite: often cut into beads, cameos, intaglios, and cabochons, and sometimes faceted Sodalite: cabochons and beads, as well as into slabs used for inlays in boxes, clock cases, and other items CLARIETY CHARACTERISTIC: Lapis Lazuli: calcite inclusions Turquoise: gem’s degree of porosity influences influences color change, Low porosity and fine texture are more valuable in turquoise than high porosity and coarse texture, matrix resemble splotches or veins and "spider web " matrix COMMON TREATMENTS: Lapis Lazuli: treatment is common, but doesn't last and effect value, Dyeing is one of the most common to improve color & conceals calcite inclusions it is then sealed with wax or plastic, green hued lapis is heated then dyed to improve color, also lapis is impregnated with wax or oil to improve its color and luster, treatments can help the lapis interact with light better Turquoise: impregnating with colorless wax or dyed wax, plastic impregnation, Polymer-impregnated is known as "Stabilized turquoise", dyeing and dyed with black shoe polish to create patterns that look like matrix, epoxy to thin turquoise slices to strengthen and darken them, plastic surface coating, filling cavities with imitation pyrite inclusions made of metal-filled epoxy, Zachery method makes it less porous- improves color, treatments can also help the turquoise interact with light better COUNTRIES OF ORIGIN: Lapis Lazuli: Badakhshan, a province in present-day Afghanistan, is a source of top-quality lapis, mines in the country known as Bactria (700BC) oldest known commercial gemstone source that is still producing today, today it is mined in Afghanistan, Chile and Lake Baikal in Siberia, Russia. Minor sources are Angola, Canada,Pakistan, Colorado (US) mine called the Blue Wrinkle, 1999 two new lapis colors—a light cornflower blue and a blue-black shade—appeared on the market. Afghanistan grading: “Nili”—the highest-quality lapis, with the best indigo color “Asmani”—a light blue lapis, much like the color of chambray denim “Sabzi”—a greenish lapis, sometimes confused with turquoise Turquoise: China, Egypt, Chile, and new sources in the southwestern US and Iran, China's Hubei Province is the world’s major source of top-color sky blue turquoise, famous Sleeping Beauty mine in Globe, Arizona—has produced large quantities of turquoise Malachite: Australia, Russia, the US, and Zaire. It’s often found along with deposits of copper Azurite: US, Namibia, and France Azurite-malachite : US, Namibia, and France, scarce and not well known to the public "Blue John" Fluorite": England is a major source of this material Charoite: only source is Russia, and its availability is limited Onyx Marble: Major sources are Mexico and the US and considered plentiful and common Rhodochrosite: Transparent gem-quality rhodochrosite is found in China, Peru, South Africa, and the US state of Colorado, desired by collectors for its beauty and scarcity Pyrite: Sussex, England Unakite: US in North Carolina’s Unaka range Sodalite: Canada, Brazil, and Namibia COMMON IMITATION MATERIAL: Lapis Lazuli: glass and plastic, dyed feldspars, dyed calcite, and dyed howlite are commonly used to imitate lapis, "Gilson" a ceramic process, it’s composed of synthetic ultramarine (a manmade pigment) and hydrous zinc phosphates, Gilson imitation lapis is very porous, has a rate of 3 on Mohs scale, has darl violet patches and pyrite flecks mixed in Turquoise: glass and plastic are fairly common, " reconstructed turquoise"is mixture of powdered minerals, dyed and bonded with plastic or epoxy resin, Natural imitations: -Howlite, a semitranslucent to opaque mineral, is white with chalky texture and dark gray or black spiderweb matrix and can be dyed to resemble turquoise -Variscite is a translucent to opaque mineral light to medium yellowish green to bluish green, occasional yellow to brown matrix markings can resemble turquoise -Chrysocolla-in-chalcedony is translucent to semitranslucent, this US gem is an intense light blue to blue-green Hematite: imitation hematite that readily accepts stamping was developed mimic popular of intaglios MOHS SCALE: Lapis Lazuli: 5 to 6 depending on the mix of minerals Turquoise: 5 to 6 depending on porosity and texture Malachite: 3.5 to 4 ,soft with poor toughness but has good density Azurite: 3.5 to 4 ,soft with poor toughness Charoite: 5 to 6 Rhodochrosite: softness, 3.5 to 4 , make it an uncommon choice for jewelry Rhodonite: 5.5 to 6.5 Hematite: 5.5 to 6.5 MAIN SYNTHETIC PROCESS: Turquoise: Gilson Company produced by a ceramic method- semitranslucent to opaque, a light to medium blue color, often with an artificial-looking charcoal gray matrix that resembles the spiderweb pattern TRADES NAMES: Lapis Lazuli: often described as indigo, royal, midnight, or marine blue, Turquoise: "robin’s-egg blue" or "sky blue" , “Persian blue” Pyrite: "fools gold", "marcasite" used to describe pyrite in the trade (True marcasite is actually an unstable crystalline form of iron disulfide that, like some pyrite, is a bronze-yellow color) HISTORY: Lapis Lazuli: believed its history of lapis lazuli stretches back more than 6,500 years,treasured by the ancient civilizations of Mesopotamia, Egypt, China, Greece, and Rome CUTTING/TRADING CENTER: n/a