Dioptase
CuSiO3·H2OIMA symbol: Dptgrandfathered
Dioptase is a silicate mineral with the formula CuSiO3·H2O, crystallizing in the trigonal system. It has a Mohs hardness of 5, typically green in color, with a vitreous luster, a specific gravity of 3.28-3.35. Its streak is green.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | R -3 :R |
| Cell (Å, °) | a = 8.819, b = 8.819, c = 8.819; α = 111.7, β = 111.7, γ = 111.7 |
| Cell volume | 479.521 ų, Z = 6 |
| Axial ratios | 1.0000:1:1.0000calculated from COD 9007057 |
| Source structure | COD 9007057 (Physics and Chemistry of Minerals, 2002) — 1 of 2 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 7.298 | 2.607 | 4.91 | 4.074 | 2.121 | 2.718 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 62.7 | 36.4 | 27.6 | 22.4 | 22.3 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9007057; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.275 g/cm³calculated from COD 9007057 |
|---|---|
| Hardness (Mohs) | 5single sourceWikidata (CC0) 5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.28-3.35 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | greensingle sourceWikidata (CC0) greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 157.64 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Cu 40.31%, Si 17.82%, O 40.6%, H 1.28% |
Classification
| Nickel-Strunz (10th) | 9.CJ.30Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.CJ.30Wikidata (CC0) |
| Dana (8th) | 61.1.3.1Wikidata (CC0) |