Veins of amethystine quartz are apt to lose their colour on the exposed outcrop.
Purple corundum, or sapphire of amethystine tint, is called Oriental amethyst, but this expression is often applied by jewellers to fine examples of the ordinary amethystine quartz, even when not derived from Eastern sources.
The Romans had at their command, of transparent colours, blue, green, purple or amethystine, amber, brown and rose; of opaque colours, white, black, red, blue, yellow, green and orange.
The dark purple spar, called by the workmen "bull beef," may be changed, by heat, to a rich amethystine tint.