Microcline
K(AlSi3O8)IMA symbol: Mccgrandfathered
Microcline is a silicate mineral with the formula K(AlSi3O8), crystallizing in the triclinic system. It has a Mohs hardness of 6-6.5, typically white, green, red or yellow in color, with a pearly or vitreous luster, a specific gravity of 2.54-2.57.
Photos
Crystallography
| Crystal system | triclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C -1 |
| Cell (Å, °) | a = 8.5733, b = 12.9375, c = 7.2075; α = 90.53, β = 115.972, γ = 87.968 |
| Cell volume | 718.229 ų, Z = 4 |
| Axial ratios | 0.6627:1:0.5571calculated from COD 9005303 |
| Source structure | COD 9005303 (European Journal of Mineralogy, 1997) — 1 of 16 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.24 | 4.22 | 3.288 | 3.361 | 3.259 | 3.818 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 77.6 | 73.9 | 66.9 | 57.5 | 46.2 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9005303; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.572 g/cm³calculated from COD 9005303 |
|---|---|
| Hardness (Mohs) | 6single sourceWikidata (CC0) 6-6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.54-2.57 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | green, red, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 278.33 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | K 14.05%, Al 9.69%, Si 30.27%, O 45.99% |
Classification
| Nickel-Strunz (10th) | 9.FA.30Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.FA.30Wikidata (CC0) |
| Dana (8th) | 76.1.1.5Wikidata (CC0) |