Phlogopite
KMg3(AlSi3O10)(OH)2IMA symbol: Phlgrandfathered
Phlogopite is a silicate mineral with the formula KMg3(AlSi3O10)(OH)2, crystallizing in the monoclinic system. It has a Mohs hardness of 2.5, a calculated density of 3.044 g/cm3. Its streak is white.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 31 1 2 |
| Cell (Å, °) | a = 5.3235, b = 5.3235, c = 30.188; α = 90, β = 90, γ = 120 |
| Cell volume | 740.9 ų, Z = 3 |
| Axial ratios | 1.0000:1:5.6707calculated from COD 9016912 |
| Source structure | COD 9016912 (American Mineralogist, 2013) — 1 of 144 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 10.063 | 2.621 | 3.399 | 2.436 | 3.354 | 2.175 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 57.1 | 36.4 | 34 | 31.2 | 28.9 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9016912; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.044 g/cm³calculated from COD 9016912 |
|---|---|
| Hardness (Mohs) | 2.5single sourceWikidata (CC0) |
| Streak | whitesingle sourceWikidata (CC0) |
Chemistry (calculated)
| Molecular weight | 417.26 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | K 9.37%, Mg 17.47%, Al 6.47%, Si 20.19%, O 46.01%, H 0.48% |
Classification
| Nickel-Strunz (10th) | 9.EC.20Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.EC.20Wikidata (CC0) |