Crocoite – Tasmania’s mineral emblem

No. 56

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“With their superb colour, high lustre, and remarkably perfect crystallisation, they are the most beautiful natural objects, scarcely surpassed by crystals of any other known mineral.”
– R.G. Van Name, quoted by William Frederick Petterd in 1910.

Crocoite, a brilliant orange-to-red lead chromate (PbCrO4), was first described in 1832 by F.S. Beudant from material found in Siberia’s Beresov district. Crocoite is rare on a world scale, having only been found in small amounts at places such as Brazil, Romania, the Philippines, Germany and South Africa. However, in western Tasmania, nature has surpassed itself in its formation of spectacular growths of this beautiful mineral.

Crocoite usually occurs as prismatic, monoclinic crystals – to about 100 mm in length – which are frequently hollow, freestanding in cavities and on occasion in a ‘spray’ formation. The mineral is commonly found growing freely on the walls of cavities in decomposed, gossanous carbonate-sulphide veins, and in the weathered host rock.

Crocoite was first discovered in Tasmania in about 1895, at the Heazlewood mine – west of Waratah in the state’s north-west – and was shortly after found in abundance at the mines in the Dundas region. Its specimen value was recognised from about 1900, when specimens began to be distributed to museums worldwide. Despite this, crocoite was once so prolific that, for some years, it was mined and used as a flux in the Zeehan Smelters. The Adelaide, Red Lead, Dundas Extended and West Comet mines have traditionally produced the most crocoite, with all still producing specimens today.

Over the past 50 years, dedicated specimen miners have preserved a large number of specimens for museums, mineral collectors and scientific institutions. In 2003, crocoite was proclaimed as Tasmania’s mineral emblem by the then Governor, Sir Guy Green, in recognition of its beauty and rarity, reflecting not only Tasmania’s natural heritage but also our mining heritage.

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