This could be a shard of the Dark Crystal, I'll check with my source and get back to you. It probably is though so be careful of Skeksis when you wear it. But the risk is totally worth it for this cool necklace.

The Amethyst is about 1 inch (2 cm) tall and 1/2 inch (1 cm) wide. It hangs from 16 inches of delicate sterling silver chain, joined by a sterling silver lobster clasp and 1 1/2 inches of sterling extension chain. You will get this shard or one very much like it, they are all beautiful.

I hope no one drains your living essence.