This is a Valknut crystal grid made out of Birch wood. These are made to order, you can choose between approximately 4, 6, 8, 10, 12 and 14" in diameter and 4mm thick. This is just for the grid, stones much be purchased separately.
The triangle as a symbol is connected to the number three for obvious reasons. It can represent different things if it is oriented in different directions. It can symbolize gender based on how it is positioned. It will symbolize the power of the male, fire, and a false view of God when the point is directed upwards. Christians will see the triangle as a symbol of the Trinity.
The triangle is called a chalice when it points downward.