Mineral Factbook

Milarite

KCa2(Be2AlSi12)O30·H2OIMA symbol: Milgrandfathered

Milarite is a silicate mineral with the formula KCa2(Be2AlSi12)O30·H2O, crystallizing in the hexagonal system. It has a Mohs hardness of 5.5-6, typically colorless or green in color, with a vitreous luster, a specific gravity of 2.55-2.59.

Photos

Milarite specimen photo
HolDu · CC BY-SA 3.0 de · Commons
Milarite specimen photo
HolDu · CC BY-SA 3.0 de · Commons
Milarite specimen photo
HolDu · CC BY-SA 3.0 de · Commons
Milarite specimen photo
Bubenik · CC BY-SA 4.0 · Commons

Crystallography

Crystal systemhexagonal crystal systemWikidata (CC0)
Space groupP 6/m c c
Cell (Å, °)a = 10.41, b = 10.41, c = 13.845; α = 90, β = 90, γ = 120
Cell volume1299.35 ų, Z = 2
Axial ratios1.0000:1:1.3300calculated from COD 9001381
Source structureCOD 9001381 (American Mineralogist, 1991) — 1 of 11 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)3.3092.8824.165.2056.9232.745
I/I₀10072.649.443.331.328.8

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9001381; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.538 g/cm³calculated from COD 9001381
Hardness (Mohs)
5.5-6single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
2.55-2.59 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color
colorless, greensingle sourceDana, System of Mineralogy, 6th ed. (1892)
Luster
vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight999.28 g/molcalculated from the IMA formula
Composition (wt%)K 3.91%, Ca 8.02%, Be 1.8%, Al 2.7%, Si 33.73%, O 49.63%, H 0.2%

Classification

Nickel-Strunz (10th)9.CM.05Wikidata (CC0)
Nickel-Strunz (9th)9.CM.05Wikidata (CC0)