This is a Tetrahedron Crystal Grid made out of birch wood. These are 8 inches in diameter. Crystal grid and healing sets are groups of stones that go together for a purpose. Sets of crystals and stones are used for ritual and magickal or spiritual Crystal healing purposes or with Reiki-Seichim energy work for healing.Made with love, light, and positive energy, cleansed and Reiki applied before we ship out to you. Crystals are intuitively chosen for you.