2.15 carat Tasmanian Killiecrankie Diamond Set in Sterling Silver. This stunning ring is Size Q1/2 or 8 and1/4 , the stone is 8 mm diameter. Killiecrankie Diamonds have an interesting story they are found in the weathered granite gravels of Killiecrankie Bay on Flinders Island, Tasmania. These beautiful stones are in fact topaz. Topaz is a wonderful gemstone that is both hard ( 8 on Mohs scale) and has a high dispersion (flash). First gemstone found in Australia after colonization.