Ender Amethyst Ore is a block found only in The End. It drops Ender Amethyst when broken. Amethyst ore can be found throughout the islands, it is easiest to find at the bottom of the islands,
It can only be mined with a diamond pickaxe or higher (the only higher being an amethyst pickaxe itself), and it will drop 1-5 amethyst when broken-- 3 on average. A pickaxe enchanted with Fortune III averages at 5.5 amethyst per block, but can drop up to 12.
Interestingly, the Ender Dragon can still destroy the block without it dropping anything.
Before Minecraft 1.8, it's ID was 1942/0 and it was found in the Promised Land.