but sometimes doubly. The amethyst clearly formed by hydrothermal deposition, but the condition of the crystals suggests they were removed from the original site of crystallization and subsequently encapsulated in the mudstones. The deposit could be regarded, then, as both primary and secondary. The authors hypothesize that the well-shaped quartz crystals originated in the faults and veins in the surrounding limestone, and then eroded and redeposited in the residual mudstones.