Mineral Factbook

Delafossite

Cu1+Fe3+O2IMA symbol: Delgrandfathered

Delafossite is an oxide or hydroxide mineral with the formula Cu1+Fe3+O2, crystallizing in the trigonal system. It has a Mohs hardness of 5.5, typically black in color, a calculated density of 5.094 g/cm3. Its streak is black.

Photos

Delafossite specimen photo
Henk Smeets – tomeikminerals.com · CC BY 4.0 · Commons
Delafossite specimen photo
Joan Rosell, from rosellminerals.com · CC BY 4.0 · Commons
Delafossite specimen photo
Robert M. Lavinsky · CC BY-SA 3.0 · Commons
Delafossite specimen photo
Robert M. Lavinsky · CC BY-SA 3.0 · Commons

Crystallography

Crystal systemtrigonal crystal systemWikidata (CC0)
Space groupP 63/m m c
Cell (Å, °)a = 2.858, b = 2.858, c = 11.293; α = 90, β = 90, γ = 120
Cell volume79.885 ų, Z = 2
Axial ratios1.0000:1:3.9514calculated from COD 9008313
Source structureCOD 9008313 (Zeitschrift fur Kristallographie, 1983) — 1 of 2 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.4182.2672.8231.6681.4291.498
I/I₀10043.227.926.923.621.2

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9008313; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)5.094 g/cm³calculated from COD 9008313
Hardness (Mohs)
5.5single sourceDana's System, 3rd Appendix (1915)
Color
blackDana's System, 3rd Appendix (1915)
Streak
blacksingle sourceWikidata (CC0)

Classification

Nickel-Strunz (10th)4.AB.15Wikidata (CC0)
Nickel-Strunz (9th)4.AB.15Wikidata (CC0)