Ametrine is a variety of quartz. The gem form of amethyst is a violet-blue, while the color in citrine is yellow to brown. The natural combination of the two colors in these gems leads to an attractive shade of purple-yellow to purple with a slightly mottled appearance. Most often, the color zone is distinctly divided in half by lines or zones running from top to bottom through the center of each stone. Its colors come from impurities of iron, chromium and manganese. Because it is a relatively rare stone, ametrine is expensive. However, smaller gems are less costly than larger ones. Ametrine is found in the Andes mountains in Bolivia, Peru, Chile and Argentina.
