Mineral Factbook

Carnallite

KMgCl3·6H2OIMA symbol: Cnagrandfathered

Carnallite is a halide mineral with the formula KMgCl3·6H2O, crystallizing in the orthorhombic system. It has a Mohs hardness of 2.5, a calculated density of 1.6 g/cm3. Its streak is white.

Photos

Carnallite specimen photo
Hans-Joachim Engelhardt · CC BY-SA 4.0 · Commons
Carnallite specimen photo
Phyrexian · CC BY-SA 4.0 · Commons
Carnallite specimen photo
Slashme · CC BY 4.0 · Commons
Carnallite specimen photo
Slashme · CC BY 4.0 · Commons

Crystallography

Crystal systemorthorhombic crystal systemWikidata (CC0)
Space groupP n n a
Cell (Å, °)a = 16.11899, b = 22.47198, c = 9.551; α = 90, β = 90, γ = 90
Cell volume3459.6 ų, Z = 12
Axial ratios0.7173:1:0.4250calculated from COD 5000211
Source structureCOD 5000211 (American Mineralogist, 1985) — 1 of 3 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.9253.3163.0323.6022.3413.549
I/I₀10090.356.654.451.251.1

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 5000211; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)1.6 g/cm³calculated from COD 5000211
Hardness (Mohs)
2.5single sourceWikidata (CC0)
Streak
whitesingle sourceWikidata (CC0)

Chemistry (calculated)

Molecular weight277.85 g/molcalculated from the IMA formula
Composition (wt%)K 14.07%, Mg 8.75%, Cl 38.28%, H 4.35%, O 34.55%

Classification

Nickel-Strunz (10th)3.BA.10Wikidata (CC0)
Nickel-Strunz (9th)3.BA.10Wikidata (CC0)