Siderite with Phillipsite

Siderite with Phillipsite from Pioneer Quarry, Narre Warren, Melbourne, Victoria, Australia, measuring 75 × 58 × 37 mm and weighing 135 grams.

Siderite, an iron carbonate, is a less commonly reported companion to Phillipsite than the more usual Calcite or other zeolites, and finding the two together points to groundwater carrying enough dissolved iron to crystallise alongside the zeolite in the same basalt cavity. Narre Warren, in Melbourne's south-eastern suburbs, is a quieter zeolite-producing locality than better-known sites such as Bundoora, but its basalt has produced a comparable cavity mineral suite.

This specimen comes from the Allan Waldon Collection. The Siderite and Phillipsite combination makes this a slightly unusual piece within the broader group of Victorian basalt zeolite specimens, and a good conversation piece for anyone who already has the more common associations represented.