Kainite
KMg(SO4)Cl·2.75H2OIMA symbol: Kaigrandfathered
Kainite is a sulfate mineral with the formula KMg(SO4)Cl·2.75H2O, crystallizing in the monoclinic system. It has a Mohs hardness of 2.5-3, typically colorless, white or red in color, with a vitreous luster, a specific gravity of 2.067-2.188. Its streak is white; cleavage is distinct.
Photos
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C 1 2/m 1 |
| Cell (Å, °) | a = 19.72, b = 16.23, c = 9.53; α = 90, β = 94.92, γ = 90 |
| Cell volume | 3038.89 ų, Z = 4 |
| Axial ratios | 1.2150:1:0.5872calculated from COD 9000282 |
| Source structure | COD 9000282 (American Mineralogist, 1972) |
Physical properties
| Density (calculated) | 2.089 g/cm³calculated from COD 9000282 |
|---|---|
| Hardness (Mohs) | 2.5-3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.067-2.188 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | colorless, red, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | vitreousDana, System of Mineralogy, 6th ed. (1892) |
| Cleavage | distinctDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 244.46 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | K 15.99%, Mg 9.94%, S 13.12%, O 44.18%, Cl 14.5%, H 2.27% |
Classification
| Nickel-Strunz (10th) | 7.DF.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 7.DF.10Wikidata (CC0) |