Danburite
A sample of danburite
Danburite from Mexico, ~ 4 cm in height
Danburite is a crystalline mineral similar to topaz. Its chemical formula is CaB2(SiO4)2. It has a Mohs hardness of 7 to 7.5 and a specific gravity of 3.0. The mineral has an orthorhombic crystal form. It is usually colourless, like quartz, but can be also either pale yellow, yellowish-brown, or pink. It typically occurs in contact metamorphic rocks.
It is named for Danbury, Connecticut, United States where it was first discovered in 1839 by Charles Upham Shephard.
References
Source: adapted by the editor from Wikipedia, the free encyclopedia; from the article "Danburite". Image Credit.
