Amethyst is one of the more popular gemstones in jewellery. Until relatively recently, it was considered to be a precious stone much like rubies or emeralds, although it would be less so in comparison to gems such as Diamonds. Naturally it can be found in various areas such as Siberia or Brazil, with the latter containing large deposits of the stone – which directly contributed to its loss of value as it lost its rarity.
Value
Unlike other precious stones, the primary gauge of an Amethyst stone's value is not its weight in carats. These gemstones are valued by their colour, and one colour referred to as "Deep Russian" is considered to be the rarest and most valuable. Even so, their value is rarely consistent as it depends on the demand by gemstone collectors.
Colour
Amethyst can be found in a range of colours. Most commonly it appears in light pink colours, though darker stones such as purple coloured amethysts exist. Usually, it is the purple colour that is the more valuable and rare variety. It can at times display secondary hues, usually red or blue.
Interestingly, their colour is usually laid out in stripes. These tend to be arranged parallel to the final faces of the stone, which makes the gemstone's colour dependent on the cut. Due to this, an improper cut can cause the stone's colour to be altered. Of course that can also be used to manipulate the colour and for this reason it is best to exercise caution when shaping an Amethyst.
Synthetic Amethyst
It is possible to create an artificial amethyst. Laboratory grown stones tend to be made to resemble the rarer Amethyst colours, and usually have properties that are virtually identical to the natural stone. Because of this, it can be very difficult to distinguish a synthetic amethyst from a natural one without applying specialist testing. This, of course, can be costly to arrange and therefore not very practical. A method called "twinning" can be used to identify synthetic stones more easily. While twinned amethysts can be synthesized, they are not very commonly found on the market.
Properties
Amethysts are one of the harder gemstones and good quality Amethyst can be as hard as a 7 on the Mohs hardness scale (diamond being a 10). It should be noted that poorer quality examples may exhibit less hardness.
Of note is the tendency of Amethysts to have their colour fade if overexposed to light sources. Therefore it is best to store Amethyst jewellery, or gemstones, in areas shielded from light.
Sources
Amethyst deposits are most abundant in Brazil, but can be found in a variety of places. South America, United States, Russia, Austria, India, as well as South Korea, are all countries where amethyst deposits can be found. In addition, there are considerable deposits located in south Africa. Because of this, Amethyst gemstones are relatively less expensive and easier to obtain when compared to other gemstones which have their value measured by carats.