Uniqueness Guaranteed: Every item is one-of-a-kind, making them ideal for all projects or designs. Listing is for (1 Piece) Avg Size Range: (25 to 35 mm) Sizes Vary Material Origin: (Tasmania) Atlantisite is a composite stone that combines serpentine, a green magnesium silicate mineral, with stichtite, a purple to pink chromium-bearing mineral. The green and purple colors of these two minerals contrast beautifully. Atlantisite forms in serpentinite rocks, where the mineral serpentine is predominant, and stichtite occurs as a secondary mineral. Stichtite forms when serpentinite is altered in the presence of chromium and magnesium-rich fluids.