Dravite

Dravite from May Downs Station, Mount Isa, Queensland, Australia, measuring 90 × 58 × 58 mm and weighing 433 grams. A substantial piece of this tourmaline-group species from north-west Queensland's pegmatite country.

Dravite is the magnesium-dominant member of the tourmaline group, a complex borosilicate typically crystallising in trigonal prisms, usually in brown to near-black shades reflecting its magnesium-rich chemistry. The pegmatites and associated metamorphic rocks around Mount Isa, including those at May Downs Station, have produced Dravite where boron-bearing fluids reacted with magnesium-rich host rock during pegmatite emplacement or regional metamorphism, in the same broad geological setting as the district's better-known Schorl from Mica Creek.

A piece of this size is a good representative of north-west Queensland's pegmatite mineralogy, standing alongside the region's Schorl as the two ends of the same tourmaline-group story. This piece is from the David Vince Collection.