vug

A small cavity in a rock or vein, often with a mineral lining of different composition from that of the surrounding rock.

In mining, a cavity; a hollow in a rock or in a lode. Vug is the miners’ name for that which geologists more generally call a geode. See geode. Also called tick-hole, vooga-hole.

A small to medium-sized cavity inside rock that may be formed through a variety of processes.