Weilite

 Weilite (CaHAsO₄) is a rare arsenate mineral. It is a translucent white triclinic mineral with a waxy luster.^[1]

Weilite
General
Category	Arsenate mineral
Formula (repeating unit)	CaHAsO4
Strunz classification	8.AD.10
Crystal system	Triclinic
Crystal class	Pinacoidal (1) (same H-M symbol)
Space group	P1
Unit cell	a = 7.059 Å, b = 6.891 Å c = 7.201 Å; α = 97.43° β = 103.55°, γ = 87.75°; Z = 4
Identification
Color	White
Crystal habit	Powdery, massive
Fracture	Irregular/uneven
Tenacity	Brittle
Luster	Waxy, greasy, dull
Streak	White
Diaphaneity	Translucent
Specific gravity	3.48
Optical properties	Biaxial (-)
Refractive index	nα = 1.644 nγ = 1.688
Birefringence	δ = 0.044
2V angle	Measured: 81°
References

It was first described in 1963 for occurrences in Gabe Gottes Mine, Haut-Rhin, Alsace, France; Wittichen, Schenkenzell, Black Forest, Baden-Württemberg, Germany; and the Schneeberg District, Erzgebirge, Saxony, Germany. It is named after French mineralogist René Weil of the University of Strasbourg.^[1] It occurs in the oxidized zone of arsenic-bearing hydrothermal veins. It occurs as an alteration product of pharmacolite and haidingerite.

This article uses material from the Wikipedia article  Metasyntactic variable, which is released under the  Creative Commons Attribution-ShareAlike 3.0 Unported License.