Phillipsite with Chabazite

Phillipsite with Chabazite from Boral Quarry, Bundoora, Melbourne, Victoria, Australia, measuring 64 × 54 × 36 mm and weighing 137 grams.

Phillipsite and Chabazite are two of the most frequently documented zeolites from this quarry, and finding them intergrown on the one piece is a good illustration of how a single basalt cavity can host more than one zeolite species as groundwater chemistry shifts slightly during crystallisation. Phillipsite's complex twinned habit and Chabazite's rhombohedral forms are usually distinguishable from each other under reasonable light, even when they share the same small cavity.

This piece comes from the Allan Waldon Collection. At 137 grams it's one of the larger Bundoora zeolite pieces in this release, giving the combination of species some real presence in a cabinet.