Description
The mineral danburite is a boron-containing calcium silicate with the chemical formula CaB2Si2O8. The mineral belongs to the sorosilicate family. Transparent to translucent white, gray, or yellowish danburite has a vitreous to oily luster, a white streak color, and poor cleavage along the crystal plane [001]. Danburite has an average density of 2.99 and a hardness of 7. The crystal system is orthorhombic, and the mineral is not radioactive. Danburite was discovered in 1839 near Danbury, Connecticut, in the United States. Danburite occurs primarily in pegmatites and contact metamorphic rocks. Danburite is common in nature, but rarely in gem quality. Honey-yellow crystals occur on Baja California, Mexico, and clear to pink-colored stones up to 20 cm in size in Charcas, Mexico. Danburite is also found in Bolivia, Myanmar (large white and yellow crystals), and Russia. Large yellow-brown crystals come from Madagascar.
