Ludlamite
Fe2+3(PO4)2·4H2OIMA symbol: Ludgrandfathered
Ludlamite is a phosphate, arsenate, or vanadate mineral with the formula Fe2+3(PO4)2·4H2O, crystallizing in the monoclinic system. It has a Mohs hardness of 3-4, typically green in color, with a vitreous luster, a specific gravity of 3.12. Its streak is white or green.
Photos
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/a 1 |
| Cell (Å, °) | a = 10.541, b = 4.646, c = 9.324; α = 90, β = 100.43, γ = 90 |
| Cell volume | 449.084 ų, Z = 2 |
| Axial ratios | 2.2688:1:2.0069calculated from COD 9009877 |
| Source structure | COD 9009877 (Journal of Chemical Physics, 1966) — 1 of 3 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.962 | 4.909 | 2.768 | 3.004 | 3.744 | 2.542 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 83.8 | 68 | 63 | 42.8 | 42.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009877; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.177 g/cm³calculated from COD 9009877 |
|---|---|
| Hardness (Mohs) | 3-4single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.12 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | green, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 8.CD.20Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 8.CD.20Wikidata (CC0) |