Mineral Factbook

Cristobalite

SiO2IMA symbol: Crsgrandfathered

Cristobalite is an oxide or hydroxide mineral with the formula SiO2, crystallizing in the tetragonal system. It has typically colorless in color, with a vitreous luster, a specific gravity of 2.777. Its streak is white.

Photos

Cristobalite specimen photo
DaveC1 · CC BY-SA 4.0 · Commons
Cristobalite specimen photo
Leon Hupperichs · CC BY-SA 3.0 · Commons
Cristobalite specimen photo
Jing Yang; Wei Du · CC BY 4.0 · Commons
Cristobalite specimen photo
Robert M. Lavinsky · CC BY-SA 3.0 · Commons

Crystallography

Crystal systemtetragonal crystal systemWikidata (CC0)
Space groupP 41 21 2
Cell (Å, °)a = 4.9727, b = 4.9727, c = 6.9257; α = 90, β = 90, γ = 90
Cell volume171.257 ų, Z = 4
Axial ratios1.0000:1:1.3927calculated from COD 9017338
Source structureCOD 9017338 (Acta Crystallographica, Section B, 2019) — 1 of 36 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)4.0392.4862.8423.1351.8711.93
I/I₀10014.911.99.36.36.1

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9017338; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.33 g/cm³calculated from COD 9017338
Specific gravity
2.777 g/cm3single sourceDana's System, 2nd Appendix (1909)
Color
colorlesssingle sourceDana's System, 2nd Appendix (1909)
Streak
whitesingle sourceWikidata (CC0)
Luster
vitreoussingle sourceDana's System, 2nd Appendix (1909)

Chemistry (calculated)

Molecular weight60.08 g/molcalculated from the IMA formula
Composition (wt%)Si 46.74%, O 53.26%

Classification

Nickel-Strunz (10th)4.DA.15Wikidata (CC0)
Nickel-Strunz (9th)4.DA.15Wikidata (CC0)
Dana (8th)75.1.1.1Wikidata (CC0)