Mineral Factbook

Picromerite

K2Mg(SO4)2·6H2OIMA symbol: Pmrapproved

Picromerite is a sulfate mineral with the formula K2Mg(SO4)2·6H2O, crystallizing in the monoclinic system. It has typically white or green in color, a specific gravity of 2.1. Its streak is white.

Photos

Picromerite specimen photo
Aangelo · CC BY-SA 4.0 · Commons
Picromerite specimen photo
André Karwath aka Aka · CC BY-SA 2.5 · Commons
Picromerite specimen photo
Rock Currier · CC BY 3.0 · Commons
Picromerite specimen photo
Robert M. Lavinsky · CC BY-SA 3.0 · Commons

Crystallography

Crystal systemmonoclinic crystal systemWikidata (CC0)
Space groupP 1 21/a 1
Cell (Å, °)a = 9.0954, b = 12.2484, c = 6.1335; α = 90, β = 104.88, γ = 90
Cell volume660.383 ų, Z = 2
Axial ratios0.7426:1:0.5008calculated from COD 9013501
Source structureCOD 9013501 (American Mineralogist, 2009) — 1 of 2 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)3.7034.0654.1552.9652.3883.062
I/I₀10075.26456.346.643

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9013501; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.025 g/cm³calculated from COD 9013501
Specific gravity
2.1 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color
green, whitesingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922)
Streak
whitesingle sourceWikidata (CC0)

Chemistry (calculated)

Molecular weight402.72 g/molcalculated from the IMA formula
Composition (wt%)K 19.42%, Mg 6.04%, S 15.92%, O 55.62%, H 3%

Classification

Nickel-Strunz (10th)7.CC.60Wikidata (CC0)
Nickel-Strunz (9th)7.CC.60Wikidata (CC0)
Dana (8th)29.3.6.1Wikidata (CC0)