Tephroite
Mn2+2(SiO4)IMA symbol: Tepgrandfathered
Tephroite is a silicate mineral with the formula Mn2+2(SiO4), crystallizing in the orthorhombic system. It has a Mohs hardness of 5.5-6, typically brown, gray, red or rose in color, with a greasy or vitreous luster, a specific gravity of 4-4.12. Its streak is gray.
Photos
Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P b n m |
| Cell (Å, °) | a = 4.8789, b = 10.60587, c = 6.20468; α = 90, β = 90, γ = 90 |
| Cell volume | 321.061 ų, Z = 4 |
| Axial ratios | 0.4600:1:0.5850calculated from COD 9016617 |
| Source structure | COD 9016617 (Mineralogical Magazine, 1998) — 1 of 10 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.542 | 2.863 | 1.803 | 2.599 | 3.607 | 2.678 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 87.5 | 73.8 | 65.5 | 55.9 | 32 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9016617; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.189 g/cm³calculated from COD 9016617 |
|---|---|
| Hardness (Mohs) | 6single sourceWikidata (CC0) 5.5-6single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 4-4.12 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | brown, gray, red, rose, smokysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | greasy, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 9.AC.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.AC.05Wikidata (CC0) |
| Dana (8th) | 51.3.1.4Wikidata (CC0) |