Goethite psm Pyrite

Goethite pseudomorph after Pyrite, known locally as "Devil's Dice", from the Kirkeeks Treasure Mine, Olary District, South Australia, Australia, measuring 32 × 26 × 25 mm and weighing 69 grams.

A pseudomorph forms when one mineral is entirely replaced by another while retaining the original's external crystal shape, and here Goethite has taken over the cubic form of Pyrite crystals completely, leaving behind the dice-like cubes that give this material its local nickname. The Kirkeeks Treasure Mine, in South Australia's Olary Province, is specifically recognised among collectors for producing this kind of Goethite-after-Pyrite material, a historic goldfield locality where the mineralogy has outlasted the mining itself.

This piece comes from the Allan Waldon Collection. Cube pseudomorphs like this are an easy, visually direct way to explain what a pseudomorph actually is to someone new to collecting, which makes a piece like this both a solid specimen and a useful teaching example.