mineral

Agate (Chalcedony)

Silicon Dioxide (SiO2)

Hardness 6.5-7 on Mohs scale, waxy to vitreous luster, translucent to semi-opaque, microcrystalline trigonal structure, greyish-blue and brownish-orange colour banding, no cleavage, specific gravity ~2.6.

Identified July 22, 2026More mineral →

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Physical properties

Formation & geological history

Forms from low-temperature silica-rich fluids filling cavities inside volcanic rocks (such as basalt or rhyolite) or sedimentary formations. Common in the ancient volcanic regions of eastern Australia (including New South Wales and Queensland).

Uses & applications

Polished and shaped as a pendant gemstone for jewelry and ornamental lapidary collections.

Geological facts

Agates are famous for their microcrystalline silica bands, which form in concentric or subtle layered patterns as mineral-rich water precipitates layer after layer inside rock pockets.

Field identification & locations

Identified by its waxy luster, smooth polished surface, high hardness (scratches glass), and translucent color gradations. Commonly collected along riverbeds, coastal regions, and volcanic terrains in Australia.