Chrysoprase
India
6.86 carats
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General Information | ||||||
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Varieties/Types: | Amethyst - A purple variety of Quartz. Ametrine - A mixture of Amethyst and Citrine in the same crystal. Aqua Aura - Clear quartz artificially coated with thin layer of metal to turn it iridescent. Chalcedony - A cryptocrystalline variety of Quartz. Agate - A banded variety of Chalcedony. Iris Agate - An iridescent variety of Agate. Onyx - A monochromatic Agate with black and white banding. Sardonyx - A monochromatic Agate with red/brown and either black or white banding. Binghamite - Chatoyant Chalcedony with fibres of hematite/goethite. Bloodstone - A dark green/greenish-blue Chalcedony with small red blood-like spots. Carnelian - A red to orange variety of Chalcedony. Chrome-Chalcedony - Emerald green Chalcedony, colored by chromium. Chrysoprase - A green Chalcedony coloured by inclusions of Ni minerals. Dendritic Agate - A chalcedony containing contrasting branching, or dendritic, mineral inclusions. Moss Agate - A translucent chalcedony containing green strands of chlorite. Fire Agate - A variety of Agate containing iridescent spheroids of limonite. Jasper - Jasper is a dense, opaque, microcrystalline variety of Chalcedony. Dallasite - A variety of Jasper from Vancouver Island, British Columbia, Canada. Orbicular Jasper - Jasper containing numerous spherical inclusions. Petrified Wood - A decorative type of fossil wood where the original organic material has been replaced - usually by chalcedony, agate, opal, etc. Pietersite - Chalcedony with embedded fibers of amphibole minerals, causing chatoyancy. Sard - A brown to brownish-red translucent variety of Chalcedony. Citrine - A yellow to yellow-orange or yellow-green variety of Quartz. Iris Quartz - A quartz showing rainbow colours. Merlinite - Drusy quartz over psilomelane. Mystic Quartz - Clear cut quartz coated with thin layer of titanium on pavilion. Prase - Prase is a leek-green variety of Quartz. Prasiolite - A green variety of Quartz. Aventurine - A variety of Quartz containing glistening fragments, usually of mica, but sometimes hematite, goethite or chlorite. Rock Crystal - A transparent colourless variety of Quartz. Rose Quartz - Pink variety of Quartz. Rutilated Quartz - A clear Quartz shot through with golden needles of Smoky Quartz - Smoky-grey, brown to black variety of Quartz. Morion - Sometimes synonymous with Smoky quartz, but often reserved for nearly black Smoky quartz. Tiger's Eye - Chatoyant yellowish-brown variety of Quartz. | |||||
Chemical Formula |
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Synthetic Quartz | ||||||
All colors, mostly amethyst, citrine, ametrine: colors are usually intense. Standard tests limited: needle-like 2 phase inclusions, dust-like "breadcrumb" planes, whitish wisps. In synthetic quartz, if present, twinning may create a distinctive lfame-like pattern or may be seen as very thin parallel lines showing interference colors with diagnostic striated appearance. Synthetic blue: Chelsea - red. - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7 Synthetic quartz: mostly untwinned, rarely triangular sectors with interference colours, "bread crumbs", residues of the seed plate - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 9 | ||||||
Physical Properties of Quartz | ||||||
Mohs Hardness | 7Gemmological Tables (2004) , More from other references | |||||
Specific Gravity | 2.65Gemmological Tables (2004) , More from other references | |||||
Cleavage Quality | NoneGemstones (2009) , | |||||
Fracture | ConchoidalGems, Sixth Edition (2006) , More from other references | |||||
Refractive Index | 1.544 to 1.553Gemmological Tables (2004) , More from other references | |||||
Optical Character | Uniaxial/+Gemmological Tables (2004) , | |||||
Birefringence | 0.009Gemmological Tables (2004) , More from other references | |||||
Pleochroism | Weakly dichroicGemstones (2009) , | |||||
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