Browsing by Author "Hergt, JM"

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    Exceptional datolite crystals from Albion Park, New South Wales: morphology, chemistry and likely origin
    (Mineralogical Society of Victoria, 2018) Graham, IT; Colchester, DM; Cendón, DI; Lay, A; Hergt, JM; Greig, A; Larsen, JR
    Large, well-formed, semi-transparent yellow–green crystals up to 5.6 cm were found in cavities within the Late Permian Bumbo Latite Member of the Gerringong Volcanics in the now abandoned Cleary Brothers Quarry, Albion Park, New South Wales. Although labelled by the collector as calcite, these were later identified as datolite, with two distinct habits, occurring on a matrix of crystallized quartz and prehnite. The datolite contains very low concentrations of elements other than the essential calcium, silicon, oxygen and boron. Its distinctive chondrite-normalized, positive europium anomaly, when compared with datolite data from elsewhere, suggests crystallization from postdiagenetic hydrothermal fluids in the temperature range of 200–250°C. These datolite crystals are the finest ever found in Australia and rank highly with those found elsewhere in the world. © 2018 Mineralogical Society of Victoria