Peridot Grading

As many gem enthusiasts know, all gemstones are cut, treated, and graded using various methods. This is because no gemstone comes out of the earth (or from wherever it happens to form) ready to put on the market.

However, what many people don't know is that not every gemstone is the same; nor is it treated or graded the same. In this piece, we wanted to talk a bit about peridot, a lesser-known gemstone, and about how it is graded (and why it is graded this way). Read on!

What is Peridot?

Have you ever seen a gemstone that is a more earthy green than emeralds? That is peridot! Peridot forms in nature with this rich, natural green hue (often referred to as "peridot green"). And it is certainly not to be confused with an emerald, or with any other greenish colored gemstone. It was, in ancient times, thought to be the true topaz, despite the fact that it is certainly not similar to topaz.

How is (Natural) Peridot Formed?

Peridot differs from other gemstones, such as the emerald, in a couple of ways. First of all, it is not formed in the earth's crust, like other gemstones. It forms in the molten rock that makes up the upper mantle of the earth. In fact, peridot is one of only two gemstones that form in such a way. It is made up of silicate and magnesium-rich olivine materials and is often referred to as chrysolite. Second, it is a bit more susceptible to the elements (like weathering), which is why gemstone professionals believe that it cannot be found forming in the earth's crust.

The First Natural Peridot

The first naturally mined peridot was located on Topazos Island (now St. John's Island) near Egypt. It is currently considered to be one of the oldest known gemstones. For centuries, this same location was the sole source of this yellow-green gem. Perhaps because it formed so far in the earth's mantle that few people came across it before finding other types of gemstones. Today, peridot can be found in China, Burma, and even in the U.S., in New Mexico and Arizona.

How is Peridot Graded?

Most gemstones are graded using the same stone qualities. However, in some cases, the qualities are listed in different orders of importance, depending on the type of gemstone. Some qualities may also not be considered important at all for certain gemstones, because other qualities are much more critical. Many gemstones are graded on a AAAA, AAA, AA, A, and B scale--with AAAA being a perfect grade and B being a satisfactory grade. It is important to keep in mind that AAAA natural gemstones are extremely rare, and those that fit that grade are in museums.

The qualities that have the most impact on peridot grading are:

• Color (the integrity of the color, as well as the demand for it)
• Cut
• Clarity
• Symmetry (the stone's proportions and balance of facets)
• Finish/polish (smoothness, lack of chips and cracks)
• Window (a space that allows for through-and-through light passage, without any reflection back to the stone's surface)
• Rarity

What Has the Most Impact on Peridot's Grade?

For the peridot, in particular, cut and color are often the most important. Because it is a “softer” gemstone, meaning that it is susceptible to weathering and other types of damage IF it is not carefully extracted and crafted, color and cut are more important factors in the peridot's grading than other qualities. The color, for example, will tell a great deal about peridot inclusions, which is a big part of any gemstone's grading.

That does NOT mean it is a lesser quality gemstone; in fact, the opposite is often true. It simply means that it must be treated with greater care than diamonds or emeralds. However, though the cut is important to the peridot's grading, not every cut is suitable for every kind of gemstone.

Can You Cut Peridot Into Any Shape?

While it is theoretically possible to cut any stone into any of the popular cuts you see on the market, it isn't always practical. For instance, softer gemstones (like peridot) must be treated with greater care, and therefore may not be viable for certain cuts that require more of the gemstone to be ground away. Also, there are gemstones that, because of their natural inclusions and facets, may look cloudy or unimpressive when cut in a certain fashion.

For those of you who are interested, the most popular cuts for the peridot gemstone include oval, princess, brilliant (the other square cut besides princess-cut), cushion, domed and round. So, you would be able to find beautiful cushion cut peridot jewelry, or a peridot engagement ring. Emerald cut peridot necklaces are also quite popular.

Should You Buy Natural or Lab Grown Peridot?

You should know that lab grown, and lab treated gemstones are very much as real as those that are mined straight from the earth. Therefore, there is no real difference in the quality of one over the other. In fact, the only true, noticeable difference between the two is going to be their origin and the price on the market.