Laumontite
CaAl2Si4O12·4H2OIMA symbol: Lmtapproved
Laumontite is a silicate mineral with the formula CaAl2Si4O12·4H2O, crystallizing in the monoclinic system. It has a Mohs hardness of 3.5-4, typically white, gray, red or yellow in color, with a pearly or vitreous luster, a specific gravity of 2.25-2.36. Its streak is red.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C 1 2/m 1 |
| Cell (Å, °) | a = 14.7514, b = 13.0827, c = 7.5648; α = 90, β = 111.997, γ = 90 |
| Cell volume | 1353.64 ų, Z = 4 |
| Axial ratios | 1.1276:1:0.5782calculated from COD 9007276 |
| Source structure | COD 9007276 (Physics and Chemistry of Minerals, 2004) — 1 of 15 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 9.454 | 6.839 | 3.507 | 4.155 | 4.496 | 3.661 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 66.2 | 55.6 | 55.3 | 30.1 | 23.5 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9007276; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.192 g/cm³calculated from COD 9007276 |
|---|---|
| Hardness (Mohs) | 3.5-4single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.25-2.36 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | gray, red, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 470.44 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Ca 8.52%, Al 11.47%, Si 23.88%, O 54.42%, H 1.71% |
Classification
| Nickel-Strunz (10th) | 9.GB.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.GB.10Wikidata (CC0) |
| Dana (8th) | 77.1.1.4Wikidata (CC0) |