Simpsonite

Al₄Ta₃O₁₃(OH)IMA symbol: Spngrandfathered

Simpsonite is an oxide or hydroxide mineral with the formula Al4Ta3O13(OH), crystallizing in the trigonal system. It has a calculated density of 6.817 g/cm3. Its streak is white.

Photos

Simpsonite specimen photo — Robert M. Lavinsky · CC BY-SA 3.0 · Commons

Crystallography

Crystal system	trigonal crystal systemWikidata (CC0)
Space group	P 3
Cell (Å, °)	a = 7.381, b = 7.381, c = 4.516; α = 90, β = 90, γ = 120
Cell volume	213.066 Å³, Z = 1
Axial ratios	1.0000:1:0.6118calculated from COD 9004255
Source structure	COD 9004255 (The Canadian Mineralogist, 1992)

Physical properties

Density (calculated)	6.817 g/cm³calculated from COD 9004255
Streak	whitesingle sourceWikidata (CC0)

Chemistry (calculated)

Molecular weight	875.77 g/molcalculated from the IMA formula
Composition (wt%)	Al 12.32%, Ta 61.98%, O 25.58%, H 0.12%

Classification

Nickel-Strunz (10th)	4.DC.10Wikidata (CC0)
Nickel-Strunz (9th)	4.DC.10Wikidata (CC0)