Danburite
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Description
A colorless or yellow transparent crystal occasionally used as a Gemstone. Danburite is composed of calcium borosilicate. It was named for its first reported occurrence in Danbury, Connecticut. Colorless danburite is mined in Japan and Mexico (San Luis Potosi) and yellow danburite is mined in Madagascar and Myanmar.
Synonyms and Related Terms
calcium borosilicate
Physical and Chemical Properties
- Orthorhombic system with prismatic crystals
- Poor cleavage in one direction
- Fracture = uneven to subconchoidal
- Luster = vitreous to greasy
- Streak = colorless to white
- Fluorescence = inert or strong light blue to blue-green (LW); inert or weaker violet blue (SW); red thermoluminescence
- Pleochroism = none
| Composition | CaB2Si2O8 |
|---|---|
| Mohs Hardness | 7.0 - 7.5 |
| Density | 2.93 - 3.02 g/ml |
| Refractive index | 1.630 - 1.636 |
| Birefringence | 0.006 |
Resources and Citations
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Mineralogy Database: Danburite
- R.F.Symmes, T.T.Harding, Paul Taylor, Rocks, Fossils and Gems, DK Publishing, Inc., New York City, 1997
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia: Danburite (Accessed Sept. 7, 2005 and Dec 2022)