Realgar
AsSIMA symbol: Rlggrandfathered
Realgar is a sulfide or sulfosalt mineral with the formula AsS, crystallizing in the monoclinic system. It has a Mohs hardness of 1.5-2, typically orange, red or yellow in color, with a resinous luster, a specific gravity of 3.556. Its streak is orange or red.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/n 1 |
| Cell (Å, °) | a = 9.3272, b = 13.566, c = 6.5903; α = 90, β = 106.433, γ = 90 |
| Cell volume | 799.826 ų, Z = 16 |
| Axial ratios | 0.6875:1:0.4858calculated from COD 9015711 |
| Source structure | COD 9015711 (Physics and Chemistry of Minerals, 2012) — 1 of 37 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 5.405 | 2.927 | 2.727 | 3.161 | 5.73 | 6.028 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 55 | 45.8 | 44.9 | 44.3 | 41.4 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9015711; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.554 g/cm³calculated from COD 9015711 |
|---|---|
| Hardness (Mohs) | 1.5-2single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.556 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | orange, red, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | orange, redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | resinoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 106.99 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | As 70.03%, S 29.97% |
Classification
| Nickel-Strunz (10th) | 2.FA.15aWikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.FA.15aWikidata (CC0) |
| Dana (8th) | 2.8.21.1Wikidata (CC0) |