Mineral Factbook

Alunogen

Al2(SO4)3(H2O)12·5H2OIMA symbol: Alggrandfathered

Alunogen is a sulfate mineral with the formula Al2(SO4)3(H2O)12·5H2O, crystallizing in the triclinic system. It has a Mohs hardness of 1.5-2, typically white, red or yellow in color, with a silky or vitreous luster, a specific gravity of 1.6-1.8.

Photos

Alunogen specimen photo
Pacific Museum of Earth from Canada · CC BY-SA 2.0 · Commons
Alunogen specimen photo
Pacific Museum of Earth from Canada · CC BY-SA 2.0 · Commons
Alunogen specimen photo
Pacific Museum of Earth from Canada · CC BY-SA 2.0 · Commons
Alunogen specimen photo
Zhitova, E.S.; Sheveleva, R.M.; Kupchinenko, A.N.; Zolotarev, A.A.; Pekov, I.V.; Nuzhdaev, A.A.; Davydova, V.O.; Vlasenko, N.S.; Plutakhina, E.Y.; Yapaskurt, V.O.; et al. · CC BY 4.0 · Commons

Crystallography

Crystal systemtriclinic crystal systemWikidata (CC0)
Space groupP -1
Cell (Å, °)a = 7.42, b = 26.97, c = 6.062; α = 89.67, β = 97.34, γ = 91.53
Cell volume1202.74 ų, Z = 2
Axial ratios0.2751:1:0.2248calculated from COD 9000507
Source structureCOD 9000507 (American Mineralogist, 1976) — 1 of 3 structures

Physical properties

Density (calculated)1.696 g/cm³calculated from COD 9000507
Hardness (Mohs)
1.5-2single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
1.6-1.8 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color
red, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892)
Luster
silky, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight648.41 g/molcalculated from the IMA formula
Composition (wt%)Al 8.32%, S 14.84%, O 71.56%, H 5.29%

Classification

Nickel-Strunz (10th)7.CB.45Wikidata (CC0)
Nickel-Strunz (9th)7.CB.45Wikidata (CC0)
Dana (8th)29.8.6.1Wikidata (CC0)