Plumbogummite
PbAl3(PO4)(PO3OH)(OH)6IMA symbol: Pbgredefined
Plumbogummite is a phosphate, arsenate, or vanadate mineral with the formula PbAl3(PO4)(PO3OH)(OH)6, crystallizing in the trigonal system. It has a Mohs hardness of 4-5, typically white, brown, gray or green in color, with a resinous luster, a specific gravity of 3.077. Its streak is red.
Photos
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Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | R -3 m :H |
| Cell (Å, °) | a = 7.039, b = 7.039, c = 16.761; α = 90, β = 90, γ = 120 |
| Cell volume | 719.205 ų, Z = 3 |
| Axial ratios | 1.0000:1:2.3812calculated from COD 9005405 |
| Source structure | COD 9005405 (European Journal of Mineralogy, 1999) |
Powder X-ray diffraction (calculated)
| d (Å) | 5.729 | 2.978 | 3.52 | 2.229 | 1.91 | 2.222 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 97.1 | 49.3 | 31.2 | 26.5 | 21 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9005405; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.007 g/cm³calculated from COD 9005405 |
|---|---|
| Hardness (Mohs) | 4-5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.077 g/cm3single sourceDana's System, 2nd Appendix (1909) |
| Color | brown, gray, green, red, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | resinoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 581.14 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Pb 35.65%, Al 13.93%, P 10.66%, O 38.54%, H 1.21% |
Classification
| Nickel-Strunz (10th) | 8.BL.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 8.BL.10Wikidata (CC0) |
| Dana (8th) | 42.7.3.5Wikidata (CC0) |