Braggite

Braggite is a platinum group mineral (PGM) with the chemical formula (Pt,Pd,Ni)S. It is a sulfide of platinum, palladium, and nickel, and is a major ore of platinum.

Composition and Properties:

Braggite is a metallic, opaque mineral with a bright metallic luster. Its color ranges from pale brass-yellow to greyish-white. It is isometric, typically forming as euhedral crystals or as granular aggregates. The mineral has a Mohs hardness of 5-5.5 and a distinct cleavage on {001}. Braggite is weakly magnetic.

Occurrence and Formation:

Braggite is typically found in ultramafic igneous rocks, particularly in layered intrusions associated with chromitites and other platinum group element mineralization. It occurs as a primary magmatic phase, forming directly from sulfide melts. It is often found in association with other platinum group minerals such as cooperite, laurite, and sperrylite, as well as base metal sulfides like pentlandite and chalcopyrite. Notable occurrences include the Bushveld Igneous Complex in South Africa, the Stillwater Complex in Montana, USA, and the Great Dyke in Zimbabwe.

History and Etymology:

Braggite was first described in 1932 from the Bushveld Igneous Complex. It is named after Sir William Henry Bragg and his son Sir William Lawrence Bragg, who were Nobel laureates in Physics for their work on X-ray diffraction, a technique essential for mineralogical analysis.