shadow armor official terraria wikigemcorns are a type of seed whose saplings grow into gem trees, and can be crafted from an acorn and any gem. natural gem trees can be found in the underground and cavern layer, although they are rare. generally speaking, chopping down a gem tree will yield 7 48 stone blocks, 0 11 gemcorns of the tree's type, and 0 24 gems of the tree's type (each tile of the tree has a 10*1/10 (10%) chance of dropping a gem, otherwise dropping 1 2 stone blocks, and every non barren leaf/branch tile additionally