Amethyst

Amethyst is a gem found within the Underground and Cavern layers of a world. They are obtained by breaking special blocks that have noticeable purple gemstones embedded in it. They can also be extracted from Silt, Slush, or Desert Fossil by putting them in an Extractinator. Rarely, Amethyst can be found in bulk in its own special gemstone cave, or in one that contains all of the other gems as well (besides Amber). Out of all available gems, Amethyst is the least valuable gem.

Like all other gems, Amethyst can be placed on blocks. As of 1.4.0.1, they can be crafted back into their Stony block forms at a Heavy Work Bench in a graveyard and can be obtained by cutting down an amethyst Gem Tree, dropping 0-5 of its respective gems.