Answer: vug

AnswerCrossword Clue
VUGRock cavity
VUGCavity in a rock.
VUGSmall cavity in a rock.
VUGGeode
VUGRock pocket
vuga small unfilled cavity in a lode or in rock
vuga small cavity in a rock, also VUGG, VUGH
vugsmall cavity in a rock or vein, often lined with crystals