Mineral Factbook

Åkermanite

Ca2MgSi2O7IMA symbol: Åkgrandfathered

Åkermanite is a silicate mineral with the formula Ca2MgSi2O7, crystallizing in the tetragonal system. It has a Mohs hardness of 4-5, typically colorless or white in color, with an adamantine luster, a specific gravity of 6.488. Its streak is white.

Photos

Åkermanite specimen photo
Bubenik · CC BY-SA 3.0 · Commons
Åkermanite specimen photo
Perfil57 · CC BY-SA 4.0 · Commons
Åkermanite specimen photo
Internet Archive Book Images · No restrictions · Commons
Åkermanite specimen photo
Ra'ike · CC BY-SA 3.0 · Commons

Crystallography

Crystal systemtetragonal crystal systemWikidata (CC0)
Space groupP -4 21 m
Cell (Å, °)a = 7.8348, b = 7.8348, c = 5.0087; α = 90, β = 90, γ = 90
Cell volume307.454 ų, Z = 2
Axial ratios1.0000:1:0.6393calculated from COD 9006935
Source structureCOD 9006935 (Physics and Chemistry of Minerals, 2001) — 1 of 24 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.8713.0861.7612.4782.0371.397
I/I₀10023.421.616.114.811.1

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9006935; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.945 g/cm³calculated from COD 9006935
Hardness (Mohs)
4-5single sourceDana's System, 2nd Appendix (1909)
Specific gravity
6.488 g/cm3single sourceDana's System, 2nd Appendix (1909)
Color
colorless, whitesingle sourceDana's System, 2nd Appendix (1909)
Streak
whitesingle sourceWikidata (CC0)
Luster
adamantinesingle sourceDana's System, 2nd Appendix (1909)

Chemistry (calculated)

Molecular weight272.63 g/molcalculated from the IMA formula
Composition (wt%)Ca 29.4%, Mg 8.92%, Si 20.6%, O 41.08%

Classification

Nickel-Strunz (10th)9.BB.10Wikidata (CC0)
Nickel-Strunz (9th)9.BB.10Wikidata (CC0)
Dana (8th)55.4.1.1Wikidata (CC0)