To say a gem is doubly refractive simply means that when one beam of light enters the crown, two beams of light will exit. Singly refractive means when one beam of light enters, one beam of light exits.
As a gems refractive properties are inherent in the gems crystal structure there is nothing that can be done to make a doubly refractive gem singly refractive. This is what accounts for the higher dispersion we see in moissanite when we observe them in spot lighting environments.
The other aspect is the gems refractive index. The refractive index is the measurement of the speed of light as it travels within a gem before it exits. Diamond's refractive index, one of the highest is 2.42nm. Moissanite is a whopping 2.67nm!
So ... is this a good thing or a bad thing? Neither really but what's important to know and understand is that the refractive index of a gem, in this case moissanite, can make it appear more like diamond OR NOT depending on how you cut the gem when you are targeting a specific set of optics. Let's take 2 gems, both cut to the same identical specs but one has a refractive index of 2.42nm (diamond) and the other with 2.67nm. Look how different their ASET results are.
The bottom line is this. If you are buying a moissanite and you want it to appear MOST like diamond you obviously want to get the gem whose ASET, which translates to light performance, is most like diamond. When you purchase an August Vintage Moissanite you are getting precisely this as we are perhaps one of the only companies on the planet that knows how to properly alter the gems overall proportions to mimic the optics and light return of their diamond counterparts be it Hearts & Arrows, August Vintage Cushion, European Cut or any shape it is that we are going to feature. AV Moissanite does just this.
This is an actual ASET of an AV Moissanite Hearts & Arrows next to what we most commonly see on the market worldwide. Besides adapting the proportions and refractive index of our moissanites to mimic diamond optics there is also a world of difference in the precision of the cutting. We will cover these aspects in our next article.
]]>Moissanite is a laboratory grown gem which is perhaps the most "diamond looking" material on the market. It's a durable gem that scores a 9.25 on the mohs hardness scale while diamond stands at 10 (the hardest) with ruby, sapphire and corrundum gems at 9.0. That's pretty darn tough for a gem which makes it ideal and suitable for wearing in every day jewelry. Here is a neat video produced by C&C answering this very question.
When moissanites were introduced I wasn't thrilled. They were cut sloppily (kinda like cz's are) and had an unseemly green tint. They did generate enough thermal heat though to fool the common diamond testers on the market and there were jewelers and consumers getting burned by dishonest business people. Hence we never carried them in our family store at that time. Fast forward to this past year.
A new composition was introduced to the growing of moissanite called 4H, which has given moissanite growers the ability to produce colorless (D-F) and near colorless (G-J) gems. This is all well and good but what is it that truly separates the best, most diamond looking moissanites from their common counterparts? THAT we will explore in our next blog post of Super Ideal Cut Moissanites.
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