Geomancer

Geomancers are very strange and terrifying illagers that only spawn in the deepslate layer of the caves. They summon magical pillars to trap and explode you, which can be quite a dangerous combo.

They drop amethyst shards and amethyst dust.

They also drop the "Crystalline" armor trim 1/8th of the time if the armor trim addon is installed.

Look at those tattered clothes and ratty beard... he's been down in the caves a while.