Eucryptite
LiAlSiO4IMA symbol: Ecpgrandfathered
Eucryptite is a silicate mineral with the formula LiAlSiO4, crystallizing in the trigonal system. It has a Mohs hardness of 6.5, typically colorless or white in color, a specific gravity of 2.667. Its streak is white.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | P 64 2 2 |
| Cell (Å, °) | a = 10.497, b = 10.497, c = 11.2; α = 90, β = 90, γ = 120 |
| Cell volume | 1068.76 ų, Z = 12 |
| Axial ratios | 1.0000:1:1.0670calculated from COD 9000367 |
| Source structure | COD 9000367 (American Mineralogist, 1973) — 1 of 10 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.529 | 1.915 | 1.442 | 1.642 | 4.545 | 1.23 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 21.1 | 10.7 | 9.8 | 8.6 | 5.8 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9000367; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.349 g/cm³calculated from COD 9000367 |
|---|---|
| Hardness (Mohs) | 6.5single sourceWikidata (CC0) |
| Specific gravity | 2.667 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | colorless, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
Chemistry (calculated)
| Molecular weight | 126.01 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Li 5.51%, Al 21.41%, Si 22.29%, O 50.79% |
Classification
| Nickel-Strunz (10th) | 9.AA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.AA.05Wikidata (CC0) |