Rainbow Aura Quartz is a natural Quartz Crystal that has been permanently treated by fusing titanium and niobium to it in a vacuum. It is the Titanium that gives it it's magical colours.
Aqua / Angel aura quartz is created in a vacuum chamber from quartz crystals and gold vapour by vapour deposition. The quartz is heated to 871 °C (1600 °F) in a vacuum, and then gold vapor is added to the chamber. The gold atoms fuse to the crystal's surface, which gives the crystal an iridescent metallic sheen.