Mineral Factbook

Pyrope

Mg3Al2(SiO4)3IMA symbol: Prpgrandfathered

Pyrope is a silicate mineral with the formula Mg3Al2(SiO4)3, crystallizing in the cubic system. It has a Mohs hardness of 7.5, a specific gravity of 8.888. Its streak is white.

Photos

Pyrope specimen photo
Lech Darski · CC BY 4.0 · Commons
Pyrope specimen photo
Lech Darski · CC BY-SA 3.0 · Commons
Pyrope specimen photo
Parent Géry · Public domain · Commons
Pyrope specimen photo
Géry PARENT · Public domain · Commons

Crystallography

Crystal systemcubic crystal systemWikidata (CC0)
Space groupI a -3 d
Cell (Å, °)a = 11.4508, b = 11.4508, c = 11.4508; α = 90, β = 90, γ = 90
Cell volume1501.44 ų, Z = 8
Axial ratios1.0000:1:1.0000calculated from COD 9014097
Source structureCOD 9014097 (American Mineralogist, 2011) — 1 of 65 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.561.532.8631.5882.4412.246
I/I₀1006854.744.334.426.1

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9014097; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)3.567 g/cm³calculated from COD 9014097
Hardness (Mohs)
7.5single sourceWikidata (CC0)
Specific gravity
8.888 g/cm3single sourceDana's System, 1st Appendix (1899)
Streak
whitesingle sourceWikidata (CC0)

Chemistry (calculated)

Molecular weight403.13 g/molcalculated from the IMA formula
Composition (wt%)Mg 18.09%, Al 13.39%, Si 20.9%, O 47.63%

Classification

Nickel-Strunz (10th)9.AD.25Wikidata (CC0)
Nickel-Strunz (9th)9.AD.25Wikidata (CC0)
Dana (8th)51.4.3a.1Wikidata (CC0)