Huttonite

Huttonite is a thorium nesosilicate mineral with the chemical formula ThSiO4 and which crystallizes in the monoclinic system. It is dimorphous with tetragonal thorite, and isostructual with monazite. An uncommon mineral, huttonite forms transparent or translucent cream–colored crystals. It was first identified in samples of beach sands from the West Coast region of New Zealand by the mineralogist Colin Osborne Hutton (1910–1971). Owing to its rarity, huttonite is not an industrially useful mineral. Huttonite is a thorium nesosilicate mineral with the chemical formula ThSiO4 and which crystallizes in the monoclinic system. It is dimorphous with tetragonal thorite, and isostructual with monazite. An uncommon mineral, huttonite forms transparent or translucent cream–colored crystals. It was first identified in samples of beach sands from the West Coast region of New Zealand by the mineralogist Colin Osborne Hutton (1910–1971). Owing to its rarity, huttonite is not an industrially useful mineral. Huttonite was first described in 1950 from beach sand and fluvio-glacial deposits in South Westland, New Zealand, where it was found as anhedral grains of no more than 0.2 mm maximum dimension. It is most prevalent in the sand at Gillespie's Beach, near Fox Glacier, which is the type location, where it is accompanied by scheelite, cassiterite, zircon, uranothorite, ilmenite and gold. It was found at a further six nearby locations in less plentiful amounts. Huttonite was extracted from the sands by first fractionating in iodomethane and then electromagnetically. Pure samples were subsequently obtained by handpicking huttonite grains under a microscope. This was accomplished either in the presence of short wave (2540 Å) fluorescent light, where the dull white fluorescence distinguishes it from scheelite (fluoresces blue) and zircon (fluoresces yellow), or by first boiling the impure sample in hydrochloric acid to induce an oxide surface on scheelite and permitting handpicking under visible light. Hutton suggested the huttonite contained in the beach sand and fluvio-glacial deposits originated from Otago schists or pegmatitic veins in the Southern Alps. In addition to New Zealand, huttonite has been found in granitic pegmatites of Bogatynia, Poland, where it associated with cheralite, thorogummite, and ningyoite; and in nepheline syenites of Brevik, Norway.