A granite quarry in Victoria’s northwest.
Featured image: Schorl tourmaline, Pyramid Hill
From Mindat – Two quarries, one abandoned, the other operated by E.B. Mawson and Sons, have been excavated on the low granite knolls south of the main Pyramid Hill peak in the Terricks Range, in northern Victoria. The granite varies from even-grained to coarsely porphyritic, and contains quartz, cream to white microperthitic feldspar, albite-oligoclase, biotite and muscovite. Small andalusite crystals are present. In the operating quarry, aplite and pegmatite veins occur, as well as pegmatitic patches and miarolitic cavities lined with quartz, microcline, albite and muscovite. Aggregates of black schorl crystals are common, but masses of pale blue topaz are rare. The Pyramid Hill granite is a fractionated S-type with similar P contents to the Lake Boga Granite. In the Pyramid Hill quarry, fluorapatite crystals are much less abundant than at Lake Boga. Cream to dark greyish green crystals up to several centimetres across and druses of colourless crystals several millimetres across have been collected.