Amethyst

Amethyst is related to agate and other less valuable varieties of quartz. Amethysts are a deep purple hue and are normally facet-cut into brilliant gems. Amethysts are rumored to ward off drunkenness or even nullify poisons, and as such are usually used as ornaments for mugs and chalices, particularly those used by nobility. This ward is more superstition than truth. A typical specimen has a base value of 100gp.