Dravite

specimen number:
2133388

location:
South Deposit, Yinnietharra, Western Australia, Australia

description:
Lustrous brown crystals of dravite to 3.5 cm in size in a cluster with little matrix. In great condition.

The South Deposit at Yinnietharra, located within Yinnietharra Station in the Gascoyne region of Western Australia, is a specialized open-cut mining site renowned for its significant yield of distinct mineral crystals. Geologically, the deposit is situated within the Proterozoic-aged Gascoyne Province and is hosted within a localized zone of biotite-muscovite-plagioclase schist that has undergone intensive regional metamorphism and hydrothermal alteration. This specific zone, measuring approximately five meters wide and several hundred meters long, provided the necessary pressure, temperature, and chemical environment for dense crystal concentrations to develop within the micaceous matrix. First discovered in 1918, the site experienced its primary era of commercial industrial exploitation between 1968 and 1971 when operator A. Soklich extracted roughly 12 tons of specimens, with subsequent deep-level excavation resuming in 2010 under updated mining leases.

Dravite is a magnesium-rich mineral species belonging to the diverse tourmaline group, and it crystallizes in the trigonal system. Geologically, it develops primarily within metamorphic environments, such as pelitic schists, marbles, and contact metasomatic zones where boron-bearing fluids interact with magnesium-rich host rocks. The mineral is characterized by its vitreous to dull luster, a Mohs hardness of 7 to 7.5, and a typical color profile that ranges from deep amber-brown and dark brown to near-black. It frequently occurs as stout, well-formed prismatic crystals with distinctive rhombohedral or trigonal terminations.

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