This item is made of raw tumbled Black Tourmaline and comes on an adjustable band. A true statement piece that you can stack or wear alone! Mystical Tradition says to rub black tourmaline for luck and happiness. This reputation as a powerful stone and a very lucky stone, might come from the piezoelectric qualities. When the tourmaline is rubbed it becomes charged with magnetic electricity and the luck intensifies. Stones measure approximately: 10-15 mm *This item is made to order, each rock is raw and unique to its own. Each order will be similar to the pictures listed.