Braggite

Braggite
Braggite
General
Category	Sulfide mineral
Formula (repeating unit)	(Pt,Pd,Ni)S
IMA symbol	Bg[1]
Strunz classification	2.CC.35a
Dana classification	2.8.5.3
Crystal system	Tetragonal
Crystal class	Dipyramidal (4/m) H-M symbol: (4/m)
Space group	P42/m
Unit cell	a = 6.367 Å, c = 6.561 Å; Z = 8
Identification
Color	Steel grey; white in reflected light
Crystal habit	Prismatic crystals and rounded grains
Twinning	Rarely observed
Cleavage	None
Mohs scale hardness	1.5
Luster	Metallic
Diaphaneity	opaque
Specific gravity	10 (measured) 9.383 (calculated)
Optical properties	Anisotropism distinct in polished section
References	[2][3][4][5]

Braggite is a sulfide mineral of platinum, palladium and nickel with chemical formula: (Pt, Pd, Ni)S. It is a dense (specific gravity of 10), steel grey, opaque mineral which crystallizes in the tetragonal crystal system.^[3] It is the central member in the platinum group end-members cooperite and vysotskite.

It was first described in 1932 for an occurrence in the Bushveld Igneous Complex of South Africa. Its name came from William Henry Bragg (1862–1942) and his son, William Lawrence Bragg (1890–1971). It was the first mineral that was discovered with the assistance of X rays.^[4][5]

It occurs as magmatic segregations in layered igneous intrusions such as Bushveld, the Stillwater igneous complex, the Lac des Îles igneous complex, the island of Rùm intrusive, the Great Dyke and many others.^[4][5] It is one of the most common platinum group minerals.