By Brecken Branstrator
The new Gübelin Gemstone Rating system will evaluate gems based on their quality, rarity and salience to give them a rating between 75 and 100.
Lucerne, Switzerland—The Gübelin Gem Lab wants to make it easier to talk about and compare colored gemstones.

With diamonds, communicating the 4Cs immediately tells people what kind of stone they are getting.

But as anyone who works with colored stones can attest, communicating the quality, color, and attractiveness of a gem is a different story.

In response, the lab has introduced the Gübelin Gemstone Rating, a system designed to give points to a gem’s overall impression, Raphael Gübelin, president of the House of Gübelin, explained to National Jeweler.

Knowing it needed to be simple and effective, the lab created a comprehensive system based on points, inspired by the system used to express the quality of a wine’s vintage.

The Gübelin Gemstone Rating looks at three factors: quality, rarity and salience.

The key factor in this is, of course, quality, rating such visual aspects as color, clarity/transparency and cut.

Rarity evaluates the type of gemstone, its weight and any treatments used to enhance the gemstone.

Lastly, salience describes the uniqueness of the gem and its ability to stand out.

Experts at the lab will use these parameters to calculate a point value to communicate the beauty and rarity of a stone in one number.

High-quality gems receiving at least 75 out of 100 points will qualify for a rating.

Additionally, the gems will be assigned a designation based on their Gübelin Points rating: “exceptional” for those rated 100-97.5; “outstanding” for scores 97.4-95; “excellent” for those receiving 94.9-92.5; “superior” for 92.4-90 points; “fine” for 89.9-85 points; “good”’ for 84.9-80; and “fair” for 79.9-75 points.

20201118 Gubelin rating insertGems that receive a Gübelin Rating also are assigned a designation, such as “exceptional” for those very fine gems that rate between 100 and 97.5 points.

The point system will allow the trade to be able to compare colored gems and assist in buying decisions, the lab said.

Currently, if you give someone in the trade a color and budget, they could come back with any number of options, Gübelin said.

“It would be much more efficient to have additional information saying, ‘I want a blue sapphire, 3 carat with nice color and in rating of 85 or 90.’ That already starts reducing the number of possibilities tremendously. It will help to get much closer to what’s desired.”

This will also allow consumers to better understand colored gemstones.

The lab developed the Gübelin Gemstone Rating for high-quality mined colored stones. Stones subjected to heavy treatments and lab-grown gems fall outside of its scope.

To start, Gübelin will add the service free of charge to its reports.

“The gemstone rating offers more orientation and we think more people will be interested in colored gemstones,” Gübelin said. “End-consumer will profit—and of course the industry, too.”

After some time, the service will be offered for a fee of 100 CHF (about $110 at current exchange rates) for a Gemstone Rating in combination with a gemological report.

A rating on its own costs 250 CHF (about $274), and the lab said it will give ratings to stones with reports from another lab.

The Gübelin Gemstone Rating is currently available from the company’s Lucerne laboratory only.

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