Polar Bear peninsula, Norseman, Dundas Shire, Western Australia, Australiai

Regional Level Types
Polar Bear peninsula	Peninsula
Norseman	Town
Dundas Shire	Shire
Western Australia	State
Australia	Country

The type locality for putnisite, discovered in 2007 by David Vaughan, while working for a local prospecting company. The peninsula is a remote location about 40 kilometers north-east of Norseman and surrounded by the usually dry Lake Cowan salt-pan.

David Vaughan sent specimens to the CSIRO (Commonwealth Scientific and Industrial Research Organisation), who forwarded them to Dr. Peter Elliott at the University of Adelaide. The material was determined to be a new species, with unique chemistry and a structure unlike any other minerals. The species was IMA approved in 2012. It is named after Australian mineralogists Andrew and Christine Putnis.

The putnisite material came from Halls Knoll Gossan on the peninsula. The gossan is an oxidation zone of massive nickel sulphides, and the gossan has extremely high levels of Ni, Cu, and platinum group metals. The putnisite is found in quartz and a dark green almost amorphous Cr silicate.

NOTE: "All specimens from the type locality are in museum collections. I am aware of at least five dealers who have sold Armstrong Mine specimens labelled Polar Bear peninsula. Anyone who has purchased putnisite specimens labelled Polar Bear peninsula should ask for a refund." (information Peter Elliott, Sept. 2019).

The species forms in the oxidation zones of komatiite and diorite lodes containing sulphide minerals. Putnisite forms translucent purple pseudocubic crystals under 0.5 mm. Specimens need to be handled with care, as the Mohs hardness is only 1.5 to 2.0. Putnisite is found in a quartz matrix and near amorphous Cr silicate. It has a vitreous lustre, brittle, shows one excellent and two good cleavages, fractures unevenly.

A few specimens have been seen on the market from the original discovery. The specimens are miniature, with the putnisite best seen under magnification. According to personal communication with David Vaughan, the amount of material found at the location was tiny, and the number of specimens available made public were few as a result. In 2012, the second known occurrence of putnisite was found elsewhere in the region at the abandoned Armstrong nickel mine. The specimens from this location were better, but a bench collapse buried the deposit under tons of earth, again limiting the number of specimens available.

Anaconda discovered Hall's Knoll probably in the late 1960s, as malachite stained gossan on a small island, just east of a small headland from the peninsula.

The host is serpentinite, talc, carbonate, tremolite, chlorite, with metasedimentary layers, and metagabbro units. The gossan is in talc schist, associated with metasediments. The sulphides are in serpentine, containing millerite, pyrrhotite, chalcopyrite, and pyrite (per Kim Macdonald).

Other Regions, Features and Areas containing this locality

References