Mineral Factbook

Creedite

Ca3Al2(SO4)(OH)2F8·2H2OIMA symbol: Ceegrandfathered

Creedite is a halide mineral with the formula Ca3Al2(SO4)(OH)2F8·2H2O, crystallizing in the monoclinic system. It has a calculated density of 2.739 g/cm3. Its streak is white.

Photos

Creedite specimen photo
Didier Desouens · CC BY-SA 3.0 · Commons
Creedite specimen photo
Parent Géry · CC BY-SA 3.0 · Commons
Creedite specimen photo
Parent Géry · CC BY-SA 3.0 · Commons
Creedite specimen photo
Parent Géry · CC BY-SA 3.0 · Commons

Crystallography

Crystal systemmonoclinic crystal systemWikidata (CC0)
Space groupC 1 2/c 1
Cell (Å, °)a = 13.936, b = 8.606, c = 9.985; α = 90, β = 94.39, γ = 90
Cell volume1194.02 ų, Z = 4
Axial ratios1.6193:1:1.1602calculated from COD 9009298
Source structureCOD 9009298 (Neues Jahrbuch fur Mineralogie, Monatshefte, 1983)

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)3.4747.3166.9482.1613.9073.95
I/I₀10074.373.561.561.253.6

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009298; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.739 g/cm³calculated from COD 9009298
Streak
whitesingle sourceWikidata (CC0)

Chemistry (calculated)

Molecular weight492.29 g/molcalculated from the IMA formula
Composition (wt%)Ca 24.42%, Al 10.96%, S 6.51%, O 26%, H 1.23%, F 30.87%

Classification

Nickel-Strunz (10th)3.CG.15Wikidata (CC0)
Nickel-Strunz (9th)3.CG.15Wikidata (CC0)