Mineral Factbook

Cummingtonite

܆Mg2Mg5Si8O22(OH)2IMA symbol: Cumredefined

Cummingtonite is a silicate mineral with the formula ܆Mg2Mg5Si8O22(OH)2, crystallizing in the monoclinic system. It has a calculated density of 3.28 g/cm3.

Photos

Cummingtonite specimen photo
James St. John · CC BY 2.0 · Commons
Cummingtonite specimen photo
Shannon Heinle · CC0 · Commons
Cummingtonite specimen photo
Géry PARENT · CC BY-SA 4.0 · Commons
Cummingtonite specimen photo
Géry PARENT · CC BY-SA 4.0 · Commons

Crystallography

Crystal systemmonoclinic crystal systemWikidata (CC0)
Space groupC 1 2/m 1
Cell (Å, °)a = 9.522, b = 18.1833, c = 5.3184; α = 90, β = 102.02, γ = 90
Cell volume900.646 ų, Z = 2
Axial ratios0.5237:1:0.2925calculated from COD 9001910
Source structureCOD 9001910 (American Mineralogist, 1998) — 1 of 14 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)8.2892.7453.062.5032.6193.253
I/I₀10092.17262.449.548

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9001910; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)3.28 g/cm³calculated from COD 9001910

Classification

Nickel-Strunz (10th)9.DE.05Wikidata (CC0)
Nickel-Strunz (9th)9.DE.05Wikidata (CC0)
Dana (8th)66.1.1.1Wikidata (CC0)