This is a Crown Chakra Crystal Grid made out of birch wood. These are made to order. You may choose between 4, 6, 8, 10 or 12 inches in diameter. All grids are 1/4 inch thick. Crystal grid and healing sets are groups of stones that go together for a purpose. Sets of crystals and stones are used for ritual magickal or spiritual crystal healing purposes or with Reiki-Seichim energy work for healing.