Amethyst from Brazil, from Trevor Gray's collection. Photos of Peter McIntosh. : A hobby that really rocks (+ video)

What was a lounge, plus two other rooms and a shed at Trevor Gray’s Dunedin home, have been requisitioned to house his extensive rock collection. : A hobby that really rocks (+ video)

Trevor Gray (76), of Dunedin, holds pieces of rhodochrosite (left), from Argentina, and malachite, from the Congo. : A hobby that really rocks (+ video)

Otago Rock and Mineral Club members Frank van Betuw and Angela Brookes look at an emerald rock from club president Lise Humphreys' personal collection. : A hobby that really rocks (+ video)

An elephant carved from Australian ribbonstone. Photo of Peter McIntosh. : A hobby that really rocks (+ video)

Rock fossicker Les Gibson, of Dunedin, displays a prized iron and magnesium-rich hornblende crystal he found at Kakanui, south of Oamaru, about 15 years ago. Photo: Bruce Munro : A hobby that really rocks (+ video)