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If you like the color purple, then you're probably aware that amethyst is the most famous of purple gemstones. After all, it's a fairly common stone, and people find it to be a good value. Moreover, it is February's birthstone. Yet, it wasn't always that way. Before the discovery of this purple gemstone in Brazil, they were considered quite rare and expensive: almost as much so as rubies, sapphires and emeralds.
Additional supply wasn't kind to amethyst prices for investors, but it's now an excellent budget choice if you want to give yourself (or someone you love) a lovely piece of jewelry. So, what should you know about amethyst and its distinctive color?
A Matter of Chemistry
At its most basic, amethyst is simply purple quartz, or Silicon Dioxide (SiO2). Some types of quartz have a specific variety name (citrine) while others are called by their color (rose quartz). This mineral has a hardness of 7, making it significantly softer than many other gemstones.
In particular, this means it can be used in jewelry that's worn regularly, but a purple quartz engagement ring would have to be polished after a few years. Nobody will say that amethyst is a “wrong” choice for that type of jewelry, but it has significant drawbacks over the more traditional sapphire or diamond ring.
How are Amethysts Formed?
Amethysts are formed from an otherwise colorless mineral when iron is added to the crystal structure. However when the entire crystal is exposed to radiation and heat, the iron makes it turn purple. The more iron and radiation, the darker the purple color.
However, there are situations where the iron can be placed in such a way that there's a deeper color with less iron. In this way, amethyst requires certain chemical and geological conditions to be present during crystal formation.
Occurrence of Amethyst
Amethyst is relatively common, with small deposits in a lot of locations. However, there are some larger deposits that are more commercially viable. Historically, the best amethyst was mined in the Alpine regions of Germany and Austria, as well as the Urals and Siberia in Russia, and lastly Afghanistan.
Because of the significant deposits in Europe and Central Asia, the stone has long been popular among European royalty. Over the years, most of these deposits have had the remainder of their gemstones successfully mined.
Modern-day Amethyst Mining Deposits
More recently, during the 19th century, additional gemstones were found in Africa and South America. Brazilian purple quartz is especially well known for being very clean, with few inclusions. However, it also tends to have a purple coloration that's less saturated. Rose de France amethyst is almost pink, and famously found here. Amethyst from neighboring Uruguay tends to be a rich purple, a color known as Siberian because stones mined in Siberia used to be very rich in color. Tanzanian and Zambian material tends to be more opaque but also has a rich purple color.
Amethyst Valuation and Treatments
Like most gemstones, purple quartz is valued according to the 4 C's: Cut, Color, Clarity, and Carat.
Amethysts should be expected to have a nice, uniform cut. Because amethyst is so common, it generally isn't worthwhile to buy a poorly cut stone, which can be a grade B gem. Amethysts that are graded AAAA and AAA are at the top of the line in terms of cutting and uniformity.
The darker the better, unless the amethyst is so dark that it looks black in low light. In fact, the ideal color is called Siberian purple, because that's where the deepest purple stones were once found. Look for uniform color and an even tone in your gemstone along with one that is minimizing the look of the inclusions that occur within the gem.
Most gemstones of this kind are called eye clean. This means that there are few inclusions in the faceted gem.
Large fissures make the stone less valuable. However, color is so dominant in amethyst valuation that a more opaque stone that's darker in color tends to sell for more than a cleaner Rose de France. You can see a great explanation of how it works from the GIA, including an amethyst color chart.
Has little effect on amethyst gemstone value. Quartz, in general, can grow some huge crystals, and often a large one will be cut into many small stones. For that reason, the price per carat is relatively flat.
Lastly, it's important to mention gemstone treatments. Many gems are treated to enhance their color and value. Here at With Clarity, we sell only AAA quality gemstones. However, they are heated to enhance their color and improve clarity. Heat treatment is a natural and permanent solution that makes gemstones look their best. This allows us to offer you beautiful amethyst jewelry for slightly less money than untreated stones. Best of all, heat-treated stones are just as “real” as any other amethyst.
What are the shades and colors of amethyst?
What is the difference between a lab grown and a natural amethyst?
Is amethyst safe to wear every day?