Titanium quartz is quartz which has been heat-and-vacuum treated to bond a light coating of titanium vapor to the surface of the stone. It is also known as flame aura or rainbow aura.
The same process, called vapor deposition, is used to create a treated quartz called aqua aura, except using gold vapor instead of titanium. The metallic vapor is chemically bonded to the quartz underneath but does not penetrate into the body of the stone, so if the stone is chipped, the original appearance will show through. Although quartz of this type is reputed to have special mystical properties, titanium quartz is an artificial stone manufactured similarly to aurora borealis rhinestones. Rhinestones use glass or lead crystal instead of quartz, but in all cases, a metallic vapor is bonded to a hard and translucent material to give it an iridescent sheen.