These beautiful hearts are made of natural quartz that has been specially treated to create the angel aura effect. After the stone has been carved, it is subjected to vacuum deposition to create an electrostatic bond of precious metals to the surface of the crystal. To achieve this properly, the quartz is placed in a vacuum chamber and exposed to extream heat (1600 °F!), then precious metal vapor is added. The metal bonds to the crystal, creating a beautiful metallic irridescence. These hearts are quartz coated in a combination of silver and gold.