Chemical composition -- Calcium borosilicate.
Color -- Colorless, yellow, brown, light pink.
Optics -- R.I 1.63-164.
Durability -- Hardness 7. Durable enough for use in jewelry.
Crystal structure -- Orthorhombic.
Specific Gravity -- 2.97-3.03.
Sources -- Danburite was discovered in Danbury, Connecticut, and has been found in Mexico, Myanmar (Burma), Madagascar, and Japan. Wellcut stones are very bright. Small stones are relatively abundant, but large fine stone are quite scarce.