Mineral Factbook

Ulexite

NaCaB5O6(OH)6·5H2OIMA symbol: Ulxgrandfathered

Ulexite is a borate mineral with the formula NaCaB5O6(OH)6·5H2O, crystallizing in the triclinic system. It has a Mohs hardness of 1, typically white in color, with a silky luster, a specific gravity of 1.65. Its streak is white.

Photos

Ulexite specimen photo
Albarubescens · CC BY-SA 4.0 · Commons
Ulexite specimen photo
Kevin M. Gill · CC BY 4.0 · Commons
Ulexite specimen photo
Tõnis Saadre · CC BY-SA 4.0 · Commons
Ulexite specimen photo
Beatrice Murch from Buenos Aires, Argentina · CC BY 2.0 · Commons

Crystallography

Crystal systemtriclinic crystal systemWikidata (CC0)
Space groupP -1
Cell (Å, °)a = 8.816, b = 12.87, c = 6.678; α = 90.36, β = 109.05, γ = 104.98
Cell volume688.445 ų, Z = 2
Axial ratios0.6850:1:0.5189calculated from COD 9000600
Source structureCOD 9000600 (American Mineralogist, 1978)

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)12.3717.7726.014.1632.6968.01
I/I₀10059.435.126.226.223.9

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9000600; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)1.955 g/cm³calculated from COD 9000600
Hardness (Mohs)
2.5single sourceWikidata (CC0)
1single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
1.65 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892)
Color
whitesingle sourceDana, System of Mineralogy, 6th ed. (1892)
Streak
whitesingle sourceWikidata (CC0)
Luster
silkyDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight405.24 g/molcalculated from the IMA formula
Composition (wt%)Na 5.67%, Ca 9.89%, B 13.34%, O 67.12%, H 3.98%

Classification

Nickel-Strunz (10th)6.EA.25Wikidata (CC0)
Nickel-Strunz (9th)6.EA.25Wikidata (CC0)
Dana (8th)26.5.11.1Wikidata (CC0)