A variscite deposit in semi-desert, approximately 15 km NW of Milgun Station homestead.

The mine is on the western side of Mt Deverell near the usually dry Gascoyne River, 180 kilometres north-northwest of Meekatharra. Along with Mount Deverall East, it has been the main site of variscite production in Western Australia. Between 1985 and 2005 both sites together produced a total 850 tonnes of variscite.

The variscite occurs as narrow (up to 10 cm wide) fault controlled veins near the surface. It is hosted in interbedded mudstone and shale of the Kiangi Creek Formation.

The variscite is bright green, fine-grained and generally rimmed with fine-grained white material, generally sold as foggite, although testing one such sample indicated mostly wardite with no trace of foggite; another white sample was mostly crandallite (R. Bottrill, unpublished data). But foggite has been found as grey cryptocrystalline material on some samples. Other uncommon phosphate species can be found with the variscite, along with quartz veining.

Collinsite occurs as multi-faced tapering prisms, mammillary aggregates and thin veinlets in cavities in mudstone. It also occurs as flattened fibrous aggregates to 2 cm in the mudstone bedding. It was the fourth known discovery of the species at the time. Various phosphate species listed on Mindat are named without description in the reference.

In 2012 Kim MacDonald spoke to a specimen miner, and was advised that the variscite veins were followed into the side of the hill until a fault was reached. He believed variscite possibly exists on the other side of the fault, but the material which would need to be shifted would make it unprofitable. He hoped the veins continue on the opposite side of the Gascoyne River, which he intended to search.

Other Regions, Features and Areas containing this locality

References