The Telfer gold-copper deposit is situated in the southwestern part of the Great Sandy Desert, approximately 485 kilometers southeast of Port Hedland in Western Australia.
The mine has operated since 1977 and has produced in excess of 7 million ounces of gold to date. A range of secondary minerals has been recorded from the deposit, but the mine has become famous for producing Australia's best - and arguably some of the world's best - chalcocite (copper sulfide) crystals.
Several hundred specimens of single crystals and crystal groups were collected during the late 1990s. Subsequently, Newcrest Mining generously donated most of these crystals to Australian museums and some university geology departments.
These crystals are similar to specimens originating from the Bristol copper mine in Connecticut, United States. Specimens range from single crystals to clusters to 6 cm across. The largest single crystals are more than 8 cm in length. A few crystals are on a calcite matrix or are associated with calcite crystals. Typically, the crystals are lustrous, varying from black to steel-gray.
Cruciform twins (with the shape of a cross) and penetrating crystals are common, as are elongated prismatic crystals with arrowhead terminations.