These are quite special! 10 mm grey Hackmanite cubes from Mogok, Myanmar (Burma) We've been working for over a year to source these. Ready for cabbing, spheres, drilling, wrapping or collecting! Hackmanite is truly a magical mineral that turns to a deep purple under UV light! This material is known for having strong tenebrescence. Sourced and cut in Mogok, Myanmar. Just say abracadabra! *Tenebrescence is the ability of a mineral to change color when exposed to light, in this case a UV light. The phenomena will reverse itself after a few minutes to a few hours and can be repeated again and again. Check out our UV flashlights to feel like a wizard too!