| Sanbornite | |
| Category: | Phyllosilicate |
| Formula: | Ba(Si2O5) |
| Imasymbol: | Sabn[1] |
| Molweight: | 273.50 g/mol |
| Strunz: | 9.EF.10 |
| System: | Orthorhombic |
| Class: | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Symmetry: | Pmcn |
| Unit Cell: | a = 4.62 Å, b = 7.68 Å c = 13.52 Å; Z = 4 |
| Color: | Colorless, White |
| Habit: | Platy modulated layers |
| Cleavage: | Perfect |
| Mohs: | 5 |
| Luster: | Vitreous |
| Refractive: | nα = 1.597, nβ = 1.616, nγ = 1.624 |
| Opticalprop: | Biaxial (−) |
| Birefringence: | δ = 0.0270 |
| Dispersion: | Weak |
| Streak: | White |
| Gravity: | 3.74 |
| Diaphaneity: | Transparent to translucent |
| References: | [2] [3] |
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[4] and named for mineralogist Frank B. Sanborn (1862–1936).