Named after the Achete river in Sicily, agate is a variety of crystalline quartz. In the same family as chalcedony, agate is differentiated from it’s quartz sibling by patterning and textures. It is formed by layers of silica (which can be easily seen in banded agate), often in cavities in volcanic rock or ancient lava. Agate occurs naturally in a huge variety of colours and patterns which can be cut into cabochons or faceted for jewellery making.