A new equilibrium form of zircon crystal

The surface tensions of the {100}, {110}, {101} and {211} faces are calcula ted by using Machenzie's method. A new equilibrium form of zircon crystal i s then derived on the basis of Wulf's Law. This theoretic form consists of {100} prismatic faces and {211} pyramidal faces, which is different from th at of the prediction by the periodic bond chain theory. The discovery of th e equilibrium form of zircon crystal provides a clue for understanding of t he morphology of zircon crystals formed in deep magma chamber, indicating t hat zircon morphology is an indicator of crystallization conditions.