Green crystalline

I have a friend who is attempting to build a “real” llight saber.
One of the components is crystals that when energized by a power cell
produce the light of the saber. He needs some green crystaline,
somewhat opaque rocks. I have no idea if available or where to get them. Any help?

Mack, I once read an article about a five foot long green tourmaline
crystal unearthed from Newry, Maine and rightfully called “The Jolly
Green Giant”. Is this what you are looking for?

Crystals of this size are very rare and expensive.

Jeff Simkins