CaB2Si2O8 is the chemical formula, Orthorhombic in crystal character, Refractive Index is 1.622-1.670; Birefrigenceis 0.044-0.047 Danburite can be used in jewelry due to its hardness and durability. Bright yellow onw are desirable and often cut into gems. Colorless ones are more common. You can find danburites in Myanmar, Mexico, Japan, Madagascar, USA and Russia Mogok in Burma (Myanmar) produces exceptionally fine straw yellow to bright yellow mineral specimens and cut gemstones of danburite which is usually a colorless stone. Madagascar recently is also a producer of yellow danburite but all our stones are coming from Mogok. Light pink colored stones are also known from Charcas in Mexico, which is the most important source for this rare stone. Danburite is usually found in metamorphosed limestones or in granites associated with low temperature hydrothermal activity. It is also found in evaporites. Danburite is not a well-known gemstone but is growing in popularity. When it is cut properly, Danburite makes exceptionally flashy gemstones but don?t dream to find stunning danburite on every street corner: Mogok?s production of bright yellow gems is very low and Danburite is likely to stay a beautiful connoisseur gem! The origin of danburite?s yellow color is unknown to us, it is possibly coming from some rare earth elements but we cannot be sure about this. First discovered in Danbury Connecticut, it was named after that location. Other than Mogok in Burma, the traditional sources of Danburite are Russell (New York, USA), Charcas (San Luis Potosi, Mexico) Kyushu Island (Japan), Uri (Switzerland) and more recently Madagascar island. Large Danburite crystals and mineral specimens are exceptionally rare. Small stones are more easy to get. Like topaz it belongs to the orthorhombic system and forms in wedge shaped prisms, similar to colorless topaz, but may be distinguished by their cleavage (poor in Danburite: perfect in topaz). Danburite?s crystal habits include generally prismatic crystals with a diamond-shaped cross-section. The termination shows a steeply slanted dome that produces a wedge look. It is a contrast to quartz's hexagonal prisms and pyramidal terminations. The crystals also can be rather thin to almost circular or up to a foot long and several inches across.