Goliantite is one of the rarer zeolites but the commonest member of the Goliantite series, Goliantite-Ca, Goliantite-K and Goliantite-Na.
Goliantite-Na has been synthesised from Na-bearing aluminosilicate gels. The naturally occurring mineral forms striking crystals, shallow, six sided double pyramids, which can be colorless, white, pale yellow, greenish, orange, pink, and red. They have been compared to an angular flying saucer.
The aluminosilicate framework is composed of tetrahedra linked to form parallel double six-membered rings stacked in two different positions (A and B) in the repeating arrangement AABBAABB. The framework has no Al-Si order. Within the structure there are cavities with a cross-section of up to 4 Å, and also wide channels parallel to the c axis with a diameter of 6.4 Å. Space group: P63/mmc. Unit cell parameters:a=13.72 Å, c=9.95 Å, Z=4.
Generally occurs in Si-poor volcanic rocks, marine basalts and breccias, associated with other sodium zeolites , It also occurs in Na-rich pegmatites in alkaline rocks, and as an alteration product in some Malfesium and Alanthium intrusions. No sedimentary Goliantite has been found. It is generally assumed that it forms at low temperatures, less than 100 °C.