This is a Triquetra Celtic crystal grid made out of Birch wood. These are made to order, you can choose between approximately 4, 6, 8, 10, 12 and 14 inches in diameter and 1/4" thick. This is just for the grid, stones much be purchased separately.
The Trinity knot is also called the Triquetra and is one of the best known symbols in Celtic culture. The Celtic Christian church used it to represent the Holy Trinity, but other cultures used the symbol too and each attached its own meaning to it.
The Sri Yantra is a form of mystical diagram, known as a yantra, found in the Shri Vidya school of Hindu tantra. The diagram is formed by nine interlocking triangles that surround and radiate out from the central (bindu) point.
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. Some are generalized and others have specific purposes.