Chrysocolla and quartz, DeGrussa mine, WA Collection Highlights | Updated 1 week ago Polished slab of chrysocolla and quartz from the DeGrussa copper mine, Western Australia. Geoff Deacon, WA Museum These beautiful polished slabs of blue chrysocolla and white quartz are examples of gem materials found at the DeGrussa copper mine in central WA. This mineral assemblage is rich in silica and may be the result of a shift to an arid climate in more recent geological time. An arid climate resulted in more alkaline groundwater capable of transporting silica in solution. Image: Polished slab of chrysocolla and quartz from the DeGrussa copper mine, Western Australia. Gem Collection