Peridot: The August Birthstone (and more!)

Peridot: The original birthstone for the month of August (spinel has now joined it as the month’s birthstone), Peridot may also be one of the most commonly mispronounced popular gems (looking at you too, chalcedony). Doing a quick Google search on peridot, Google tells me that it is pronounced “pere-dät”, ending with, “DOT”. According to GIA (the Gemological Institute of America) and most, if not all jewelers I have met, this gemstone name is correctly pronounced, “per-eh-DOE” or “pear-a-DOE”. Sorry, Goog.

Peridot Pronunciation

(I won’t get started on the use of “semi-precious” either, that is a story for another day.)

Historically, and dating back many hundreds of years, all green stones were considered emerald, all blue stones were sapphire and all red stones were ruby (kind of boring right?). Once gems began to be separated by class and mineral, peridot first found itself thrown into the topaz category, before it was recognized as a gem mineral in and of itself. Even more recently, the color grades for most gemstones were based on the purity of color and how much a gem looked like these popular stones. So the greener a green gemstone and the more it looked like an emerald, the more valuable. Gemstone grading has evolved a lot since then, but the value of a gemstone is still rooted in the comparison to these so-called “precious” stones.

Peridot’s color is described as yellowish green, and will never come close to emerald’s deep green hue. Some lower quality peridots can have a grayish or brownish cast, or even a milky appearance. Some of the most stunning gems I have seen and worked with come from Pakistan and have a brilliant, spring green color. Like many gemstones, in smaller sizes peridot looks very light and more yellow but in larger sizes this stone can have a bright, vivid “sunny” green color. I have always described the reason for this by using the example of a large cobalt blue glass vase, the vase itself is a rich, deep, blue color, but if you were to chip off a small shard of glass, it would be more of a sky blue. For the same reason, smaller gemstones do not have the depth of color that larger ones can. The photo below shows an example of vibrant Pakistani peridot and also shows the stone’s double refraction.

Peridot Oval Faceted

photo by Daniel McMorris

Peridot is not a gemstone that is exceptionally hard nor tough. It is not a great ring for every day, even in a protected setting, as the stone is easily scratched. Larger stones and those in prong settings in rings should be worn with care.

Interesting Peridot facts:

  1. Peridot crystals have been found in meteorites that have hit the earth, however such specimens are rare. Most commercially available peridot is mined on planet earth.
  2. The largest peridot ever found was on Saint John’s Island, also known as Zabargad, in the Red Sea. It weighs just over 311 carats and is on display in the Smithsonian Museum in Washington, D.C.
  3. Some of the beaches on the island of Oahu, Hawaii contain tiny peridot crystals and some of Hawaii’s volcanoes have produced peridot crystals large enough to cut.

 

Gemstone Durability

Gemstone durability is a commonly misunderstood subject. Being “the world’s foremost authority on gemology,” and the source of my gemological education, of course I defer to GIA (the Gemological Institute of America)  for expert advice and gem information. In this case, the subject of gemstone hardness, toughness, stability, a.k.a. gemstone durability. I have always been passionate about providing the public with practical gem advice and knowledge about the products they own and purchase, thus the reason I chose GIA education and their diploma programs.

This article from the GIA 4Cs Blog is informative, and what I especially like is the infographic showing the Mohs hardness scale. As you can see on the scale, though diamond is a 10 and corundum (ruby and sapphire) a 9, diamond is actually many times harder than a sapphire or ruby, as indicated in the sharp jump from numbers 9-10. So as you can see, the scale is not really “to scale”, but a good basic indicator of the difference in gem hardness.960x960-mohs-hardness-scale

Another important take-away from this article is the factors that contribute to a gem’s durability – it’s not all about hardness! Hardness measures a material’s resistance to scratching, where toughness measures a material’s resistance to breaking. My favorite analogy is one I believe I learned from a GIA instructor – leather is tough but not hard where glass is hard but not tough. You can scratch leather easily, but it is not easy to break. Glass on the other hard does not scratch as easily as leather, but it is quite easy to shatter.

From many years on a jewelry repair bench, I have always encouraged customers to understand at least a little bit about the jewelry they wear. Diamonds are not indestructible! Trust me, I have seen many a broken diamond in my time, and many a baffled customer. A little care goes a long way and I don’t recommend wearing any jewelry around the clock. Taking a closer look at the jewelry you wear frequently can help to identify when it might be in need of repair. Spotting a loose stone before it wiggles out of a setting can save you quite a bit in replacement costs, as can noticing a prong that looks worn or weak. Don’t take your beautiful jewelry for granted, being an educated and aware jewelry consumer will benefit you in the long run.

Click here to read the article on the GIA 4Cs Blog.