Mineral Factbook

Hardystonite

Ca2ZnSi2O7IMA symbol: Hdygrandfathered

Hardystonite is a silicate mineral with the formula Ca2ZnSi2O7, crystallizing in the tetragonal system. It has a Mohs hardness of 8.4, typically white in color, with a vitreous luster, a specific gravity of 8.396.

Photos

Hardystonite specimen photo
Nessa Eull · CC0 · Commons
Hardystonite specimen photo
Shannon Heinle · CC0 · Commons
Hardystonite specimen photo
Henk Smeets – tomeikminerals.com · CC BY 4.0 · Commons
Hardystonite specimen photo
Modris Baum · Public domain · Commons

Crystallography

Crystal systemtetragonal crystal systemWikidata (CC0)
Space groupP -4 21 m
Cell (Å, °)a = 7.8279, b = 7.8279, c = 5.0138; α = 90, β = 90, γ = 90
Cell volume307.2 ų, Z = 2
Axial ratios1.0000:1:0.6405calculated from COD 5000232
Source structureCOD 5000232 (Zeitschrift fuer Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie (-144,1977), 1969) — 1 of 4 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.873.0853.7161.7612.4755.014
I/I₀10068474442.817.2

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 5000232; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)3.391 g/cm³calculated from COD 5000232
Hardness (Mohs)
8.4single sourceDana's System, 1st Appendix (1899)
Specific gravity
8.396 g/cm3single sourceDana's System, 1st Appendix (1899)
Color
whitesingle sourceDana's System, 1st Appendix (1899)
Luster
vitreoussingle sourceDana's System, 1st Appendix (1899)

Chemistry (calculated)

Molecular weight313.73 g/molcalculated from the IMA formula
Composition (wt%)Ca 25.55%, Zn 20.85%, Si 17.9%, O 35.7%

Classification

Nickel-Strunz (10th)9.BB.10Wikidata (CC0)
Nickel-Strunz (9th)9.BB.10Wikidata (CC0)
Dana (8th)55.4.2.2Wikidata (CC0)