Sanbornite
| Sanbornite | |
|---|---|
|
sanbornite (white) with celsian (gray)—Incline, Maricopa County, California | |
| General | |
| Category | Phyllosilicate |
| Formula (repeating unit) | Ba(Si2O5) |
| Strunz classification | 09.EF.10 |
| Crystal symmetry | Orthorhombic 2/m 2/m 2/m |
| Unit cell | a = 4.62Å, b = 7.68Å, c = 13.52Å |
| Identification | |
| Formula mass | 273.50 g |
| Color | Colorless, White |
| Crystal habit | Platy modulated layers |
| Crystal system | Orthorhombic – Dipyramidal |
| Cleavage | Perfect |
| Mohs scale hardness | 5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 3.74 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.597, nβ = 1.616, nγ = 1.624 |
| Birefringence | δ = 0.0270 |
| Dispersion | Weak |
| References | [1][2] |
Sanbornite is a rare barium phyllosilicate mineral with formula BaSi2O5. Sanbornite is a colorless to white to pale green, platey orthorhombic mineral with Mohs hardness of 5 and a specific gravity of 3.74.
It was first described from Incline, Mariposa County, California in 1932 and named for mineralogist Frank B. Sanborn (1862–1936).