Mineral Factbook

Ussingite

Na2AlSi3O8(OH)IMA symbol: Usggrandfathered

Ussingite is a silicate mineral with the formula Na2AlSi3O8(OH), crystallizing in the triclinic system. It has a Mohs hardness of 6.7, typically red or violet in color, with a pearly or vitreous luster, a specific gravity of 2.495. Its streak is white.

Photos

Ussingite specimen photo
Jerry Cone · CC0 · Commons
Ussingite specimen photo
John Sobolewski (JSS) · CC BY 3.0 · Commons
Ussingite specimen photo
Emil H. Gulbransen, Henrik Friis, Fabrice Dal Bo and Muriel Erambert · CC BY-SA 4.0 · Commons
Ussingite specimen photo
Modris Baum · Public domain · Commons

Crystallography

Crystal systemtriclinic crystal systemWikidata (CC0)
Space groupP -1
Cell (Å, °)a = 7.2474, b = 7.6813, c = 8.6432; α = 90.835, β = 99.771, γ = 122.581
Cell volume396.295 ų, Z = 2
Axial ratios0.9435:1:1.1252calculated from COD 9016498
Source structureCOD 9016498 (Physics and Chemistry of Minerals, 2012) — 1 of 2 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.9852.7293.5536.4993.7564.224
I/I₀10060.85852.950.350.2

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9016498; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.533 g/cm³calculated from COD 9016498
Hardness (Mohs)
6.7single sourceDana's System, 3rd Appendix (1915)
Specific gravity
2.495 g/cm3corroboratedDana's System, 3rd Appendix (1915)
Color
red, violetsingle sourceDana's System, 3rd Appendix (1915)
Streak
whitesingle sourceWikidata (CC0)
Luster
pearly, vitreoussingle sourceDana's System, 3rd Appendix (1915)

Chemistry (calculated)

Molecular weight302.22 g/molcalculated from the IMA formula
Composition (wt%)Na 15.21%, Al 8.93%, Si 27.88%, O 47.65%, H 0.33%

Classification

Nickel-Strunz (10th)9.EH.20Wikidata (CC0)
Nickel-Strunz (9th)9.EH.20Wikidata (CC0)
Dana (8th)76.3.3.1Wikidata (CC0)