Amethyst is the most desired variety of quartz. The birthstone for the month of February, Amethyst is also the gemstone that is symbolic of the 6th and 17th wedding anniversaries. Historically the color purple represents royalty, so it should come at no surprise that this purple/violet hued semi-precious gemstone can be seen in a variety of royal possessions. The name amethyst comes from the Greek word amethustos which means not drunken. It was named for its similar color to wine. Early Greeks also believed that drinking wine from an amethyst cup would prevent intoxication.
Amethyst can be found naturally in colors ranging from grayish violet to strongly saturated violet or reddish purple. Top quality amethyst is a strong purple or reddish purple color with no color zoning.
Some other quartz varieties include citrine, rose quartz, smoky quartz, tiger’s-eye, aventurine and praseolite just to name a few. All quartz varieties are made of the same elements, silicon and oxygen. The chemical composition is, SiO2 (Silicon Dioxide).
The vibrant purple/violet color of amethyst comes from iron impurities. The difference between amethyst and citrine is the oxidized state of the iron impurities found in the quartz. Heat changes the color of amethyst. This heating occurs in nature, or by heat treatment. When the gemstone is tested for treatment or heating, there is no way to determine in what way the heating occurred. It is common to take very dark amethyst and make it a more attractive and marketable purple color. Additional heating of a dark amethyst can turn it yellow (citrine) or even green (praseolite).
Properties, Treatments & Lab Created
Amethyst is rated a 7 on the Mohs scale, which helps to make it a popular jewelry choice.
A very common treatment to Amethyst is heat treatment, to enhance or change the color. This heat treatment is used to make amethyst a rich purple color or at higher temperatures will change into citrine, a golden yellow quartz variety.
Scientists have accomplished manufacturing a lab created form of amethyst, which is identical to the natural mineral in composition. In addition to natural and lab created amethyst, there is simulated amethyst, which is made commonly from glass and colored to resemble natural amethyst.