Thulite (sometimes called rosaline) is an opaque, massive pink manganese-bearing variety of the mineral zoisite. Manganese substitutes for calcium in the structure with up to two percent Mn2+. Thulite is often mottled with white calcite and occurs as veins and fracture fillings transecting many types of rock. In mineralogical literature, thulite may sometimes refer to any pink zoisite. Clinothulite...
Tanzanite is the blue/purple variety of the mineral zoisite (a calcium aluminium hydroxy silicate) which was discovered in the Mererani Hills of Northern Tanzania in 1967, near the city of Arusha and Mount Kilimanjaro. It is used as a gemstone. Tanzanite is noted for its remarkably strong trichroism, appearing alternately sapphire blue, violet and burgundy depending on crystal orientation. Tanzanite...
Zoisite occurs in a number of varieties, the most sought-after being tanzanite, a variety colored sapphire-blue by the presence of vanadium. Tanzanite crystals have distinct pleochriosm, showing either purple, blue or slate-grey depending on the angle they are viewed from. There may also be a slight color change in incandescent light (such as that from a light blub), when stones may appear more violet....
Zoisite occurs in a number of varieties, the most sought-after being tanzanite, a variety colored sapphire-blue by the presence of vanadium. Tanzanite crystals have distinct pleochriosm, showing either purple, blue or slate-grey depending on the angle they are viewed from. There may also be a slight color change in incandescent light (such as that from a light blub), when stones may appear more violet....
Zircon is most famous for its colorless stones, which closely resemble diamonds and have been used both intentionally and mistakenly in their place. Although colorless when pure, impurities will produce yellow, orange, blue, red, brown and green varieties. Brown stones from Thailand, Vietnam and Kampuchea are usually heat-treated to change them into the colorless or blue stones popular in jewelery....
Yttrium aluminium garnet (YAG) is a synthetic crystalline material of the garnet group.
YAG for a period was used in jewelry as a diamond and other gemstone simulant. Colored variants and their doping elements include: green (chromium), blue (cobalt), red (manganese), yellow (titanium), purple (neodymium), pink, and orange. As faceted gems they are valued (as synthetics) for their clarity, durability,...
One of the first gemstones to be mined, turquoise has long been prized for its intense color, which varies from sky-blue to green, depending on the quantities of iron and copper within it. Turquoise is commonly found in microcrystalline, massive form, usually as encrustations, in veins, or as nodules. It is opaque to semi-translucent, light and very fragile, with conchoidal fracture. Some material...
