Stone Info_Feldspar, Spodumene,Diopside .pdf

*******Feldspar, Spodumene & Diopside ****** LARGEST CONSUMERS : Moonstone: In the early 1900s, the gem was popular in both Europe and the United States Sunstone: television shopping networks and other mass-market retailers, consumers in China show a strong interest, current market is a specialized...

*******Feldspar, Spodumene & Diopside ****** LARGEST CONSUMERS : Moonstone: In the early 1900s, the gem was popular in both Europe and the United States Sunstone: television shopping networks and other mass-market retailers, consumers in China show a strong interest, current market is a specialized one, consisting of upscale jewelry designers, collectors, and gem carvers, as well as tourists to the Oregon desert seeking a precious all-American souvenir Kunzite: collectors’ stone status in the US and Japan, periods of strong supply, it’s popular w/designer and massmarket jewelry styles MOHS SCALE: Moonstone: Soft, 6 to 6.5 Labradorite: fairly soft mineral that rates a 6, cleaves easily Amazonite: 6 and has 2 cleavage directions Spodumene: 6.5 to 7 with cleavage in 2 directions Chrome Diopside: toughness is also poor, hardness ranges from 5.5 to 6, two cleavage directions VARIETY/SPECIES/GROUP: Feldspar Group: includes Moonstone, Sunstone, Amazonite Pyroxene Group: Spodumene & Diopside Spodumene: three varieties- hiddenite, triphane, and kunzite COLOR/HUE RANGE/VALUE: Moonstone: range from semitransparent to opaque and colorless to white, with a blue, silver, or white adularescent effect, bodycolors vary widely from green, yellow to brown, or gray to nearly black, finest are colorless, semitransparent to nearly transparent appearance, without inclusions, with a vivid blue adularescence " Blue Sheen", finest moonstone has glassy purity with a mobile, electric blue shimmer -Rainbow Moonstone: moonstone variety displays multicolored adularescence -Parrot Green Moonstone: bright green body color, adularescence floats in this sea of green Labradorite: dark gray body color with spectral color of typically blues and greens,Transparent labradorite without phenomenal color can be colorless or pale yellow and is often facted -Spectrolite: brilliant spectral colors of fiery yellow, orange, and red as well as blue and green,spectrolite is the most desirable labradorite type Sunstone: have yellow, orange, or brown bodycolor, not all sunstones are aventurescent, appearance of phenomenon depends on the size of the inclusions, small inclusions reate a reddish or golden sheen on top any body color,Larger inclusions create attractive, glittery reflections Oregon Sunstone: range includes colorless, pale yellow, pink with brilliant aventurescence, orange, red, green, and blue-green with copper inclusions,red version are marketed as “spinel red,” and have extra sheen due to the copper inclusions,Some are either bicolored or tricolored, top deep green, deep red, and intense bicolored sunstones are considered extra-fine Amazonite: white, light orange, or pink, it’s known as amazonite or Amazon stone in its light green to greenish blue hues, grid-like white streaks and faint sheen Kunzite: Light pink is most common, but the top kunzite colors are intense pink and intense violetish purple Chrome Diopside: is a transparent, medium-dark, vivid green very little eye visible inclusions CHEMICAL COMPOSTION: Feldspar: All feldspars contain aluminum, oxygen, and silicon, but potassium, calcium, and sodium can also be major components, Two different series have been establishded: Alkali feldspars contain a mixture of potassium and sodium, & plagioclase feldspars contain a mixture of sodium and calcium Moonstone: Orthoclase moonstone is composed of two feldspar species the alkali series—orthoclase and albite Labradorite: plagioclase feldspar, it forms fine, microscopic, intergrown layers of albite and other plagioclase Sunstone: Orthoclase sunstone belongs to the monoclinic crystal system, but the plagioclase sunstone varieties— oligoclase and labradorite—crystallize in the triclinic crystal system -Aventurine feldspar: from India has a red-brown bodycolor and sunny glitter, often faceted & cabochon Amazonite: microcline feldspar and a member of the potassium-rich alkali feldspar series Chrome Diopside: Trace elements chromium or vanadium FORMING SOURCE: n/a CRYSTAL STRUCTURE: Moonstone: Orthoclase feldspar with a monoclinic crystal structure Amazonite: triclinic crystal system POSSIBLE PHENOMENA: Moonstones: adularescence, chatoyancy, and a few show four-rayed asterism,Parrot green moonstone can display pleochroism Labradorite: labradorescence Sunstone: Adventurscence sparkly, metallic luster caused by flat, reflective inclusions Chrome Diopside: can occur w/four- or six-rayed asterism or chatoyancy against a dark green to black background CLARIETY CHARACTERISTIC: Moonstone: two cleavage directions, tiny tension cracks called centipedes Sunstone: inclusions can be hematite, copper, or some other mineral Kunzite: cleavage in 2 directions, color tends to fade with exposure to bright light or high heat COMMON CUTS: Moonstone: cabochon(oval is common),beads, carvings such as cameos or the popular “man-in-themoon”,often set into pendants, earrings, and pins, calibrated stone: round 3 to 8mm, oval 6×4 to 9×7 mm and are sold by the piece, large free-form above 9×7 mm are sold by the carat Labradorite: pendants or carved and polished into objects of art, often in free-form shapes that show off its labradorescence, or used as tile in homes Chrome Diopside: tends to look dark in sizes over three carats so there often cut with shallow pavilions TRADES NAMES: Moonstone: "blue s heen", "parrot green" Sunstone: "all -American" name for Oregon sunstones COUNTRIES OF ORIGIN: Moonstone: Sri Lanka and Southern India are major source of top-quality moonstone, Lower-quality commercial grades- Myanmar and India Rainbow Moonstone: Canada and Madagascar are among the most important sources Labradorite: usually from Finland and Madagascar Sunstone: found in US state of Oregon south central area produces a number of sunstone varieties Amazonite: Brazil, India, Madagascar, Norway, Russia, and the US Kunzite: Afghanistan, Brazil, Madagascar, and the US state of California, found in pegmatites Chrome Diopside: eastern Siberia and area of Russia, great success in the gemstone market, sources have been sufficient to allow mass marketing of large quantities to television consumers, achieving sales in the tens of millions of dollars. COMMON TREATMENTS: Sunstone: isn't treated and is a big selling point of the natural "Oregon" sunstone, in 2001 an undisclosed copper-diffusion treatment for pale andesine feldspar produced vivid red and green hues that duplicated the colors of fine naturally colored sunstone Kunzite: Irradiation followed by heat treatment can create kunzite’s attractive rosy color from colorless or light-colored spodumene, Other spodumene can be irradiated as well into intense green MAIN SYNTHETIC PROCESS: n/a COMMON IMITATION MATERIAL: Sunstone: A manmade glass called goldstone often serves as a sunstone imitation but it’s often brownish orange with translucent, with small, flat copper inclusions Kunzite: imitations include glass, synthetic sapphire, and synthetic spinel HISTORY: in the early 2000's controversy around Andesine that was claimed to be from Congo, Tibet, and Inner Mongolia was actually all from a single unknown source and that was actually treated through a heating process diffusing copper into yellow andesine and labradorite feldspars. CUTTING/TRADING CENTER: n/a