Mineral Factbook

Lazulite

MgAl2(PO4)2(OH)2IMA symbol: Lzlapproved

Lazulite is a phosphate, arsenate, or vanadate mineral with the formula MgAl2(PO4)2(OH)2, crystallizing in the monoclinic system. It has a Mohs hardness of 5-6, typically blue or green in color, with a vitreous luster, a specific gravity of 3.057. Its streak is white.

Photos

Lazulite specimen photo
Geolina163 · CC BY-SA 4.0 · Commons
Lazulite specimen photo
Kaarel Tiidus · CC BY-SA 4.0 · Commons
Lazulite specimen photo
Tõnis Saadre · CC BY-SA 4.0 · Commons
Lazulite specimen photo
Mai Seppel · CC BY-SA 4.0 · Commons

Crystallography

Crystal systemmonoclinic crystal systemWikidata (CC0)
Space groupP 1 21/c 1
Cell (Å, °)a = 7.144, b = 7.278, c = 7.228; α = 90, β = 120.51, γ = 90
Cell volume323.778 ų, Z = 2
Axial ratios0.9816:1:0.9931calculated from COD 9009304
Source structureCOD 9009304 (Neues Jahrbuch fur Mineralogie, Monatshefte, 1983) — 1 of 2 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)3.2373.2023.1423.0772.5491.571
I/I₀10060.953.239.825.119.1

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009304; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)3.143 g/cm³calculated from COD 9009304
Hardness (Mohs)
5-6single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
3.057 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color
blue, greensingle sourceDana, System of Mineralogy, 6th ed. (1892)
Streak
whitesingle sourceWikidata (CC0)
whitesingle sourceDana, System of Mineralogy, 6th ed. (1892)
Luster
vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight302.23 g/molcalculated from the IMA formula
Composition (wt%)Mg 8.04%, Al 17.86%, P 20.5%, O 52.94%, H 0.67%

Classification

Nickel-Strunz (10th)8.BB.40Wikidata (CC0)
Nickel-Strunz (9th)8.BB.40Wikidata (CC0)