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Gemstone Grading System | Color, Clarity & Tanzanite

Grading gemstones, especially Tanzanite is very important. This is extra important for those looking to purchase Tanzanite and other gemstones online. Steve Moriarty from Moriarty's Gem Art explains in this video how he grades gemstones and the Tanzanite in our store.

Video Transcription

Hi, I'm Steve Moriarty from Moriarty's Gem Art. We're a jeweler on the square, in crown point. And we also represent ourselves as, which has a wide variety of color gems and jewelry. And also, which is dedicated strictly to tanzanite gems and jewelry. So, today I'd like to discuss with you a system you're going to see on our websites, that is a grading system for colored stones. Over the 45 years I've been in the business, it's been a struggle to find a system that I was confident in, that I understood, and the customer could also understand. But through discussions with an investor, Mike Dunn, who's in Florida ... he's an engineer and has been investing in tanzanite. And our discussions have what has led me to this grading system. The system is a little more complex than what I'm used to doing. It breaks down colored stones a little more accurately.

And I think you'll find that it's more understandable. And once you see the system, you're going to find that it will give you a very good idea of the quality of the stone that you're going to receive. So this is the breakdown of our gradient system. The gem is tanzanite, this one here. It's an oval, weighs 8.75 carrots. Okay, and under color, we've done something a little different. We're now grading in daylight and incandescent light. And the reason for this is many colored gems appear differently in different types of lights. Color change stones, like Alexandrite can be red in one light, and green in another. Tanzanites like this, can be much more violet in incandescent, and more blue and daylight. So we're actually breaking down the two different types of lighting, and giving them a number. This whole system is based on one to 1000, with 1000 being the best.

And in this case, this stone, in daylight graded at 950, and in incandescent graded at 900. So if you add those, divide by two, we get an an overall color grading of 925. The clarity, we've chosen to use the GIA system of color grading. That's probably the most understood of any system. People that buy diamonds are used to this system, using flawless to VVS. And in this case, it would be a 10, or a thousand is what that translates to. A VS being a nine an SI one being an eight. SI two being a seven, and I one being a five.

GIA has implemented this system, and for colored stones they have a slight variation and that's a gem type. So there's three gem types, one, two and three. Ones are typically clean stones. Twos are often seen clean, but more often have some imperfection. And type three almost always has imperfection, like emeralds and and rubellite tourmalines. So, what this does in a type one system, we just go straight from the grading. A type two would allow you a little bit of leeway in this, so an I one might be an SI two. And type three can be one or two jumps in the clarity. It's just a way of giving some latitude to stones that typically do not come clean. And it helps us in getting a better idea of what that kind of grading is, and how to price those types of stones. The third is the cut grade. We've broken it down into four different categories. The brilliance of the stone, where I'll take this around the different lights and just look at what the overall brilliance of the stone is, and give it a number from one to a thousand.

In this case it's an 875. The symmetry, I will look at the stone from four different directions. Face down, face up or looking at the table, looking down the end of the stone and looking to the side. And then, giving it, again a one to a thousand number. In this case, 825. The faceting is just how well the facets are placed, how well the facets meet. And again, give it a number from one to a thousand and this is an 850. The polish is how clean each facet is. Are there scratches, are there little divots that are a sign of under-polishing the stone? Are there chips in the Polish or scratches in the table. And these will end up giving us this number of 825. So now we take those four qualities, add them up, divide by four and that gives us this number of 844 for the cut grade.

Now we add the color, the clarity, and the cut grade, and get a number and divide by three. And that's what gives us this final grade of 923, which we call our overall cut grade. So, you'll start seeing this on our site. It will just give you a number of 900 out of a thousand. And what this kind of means is stones from say 700 to 825 would be stones we consider of good quality. The stones from 825 to 900 would be very good quality, and the stones from 900 above, are those of exceptional quality. So again, hopefully with this system of grading, the pictures that we have available and the videos of the stones ... which we feel are quite accurate, you can get a very good idea of what the stone quality is, and what that stone is going to look like when you receive it. So, thanks for watching. And I'm Steve Moriarty from Moriarty's Gem Art and Tanzanite Jewelry Designs.