Lucerne, Switzerland – The Gübelin Gem Lab wants to make it easier to talk about and compare coloured gemstones.
With diamonds, communicating the 4Cs immediately tells people what kind of stone they are getting.
But as anyone who works with coloured gemstones will tell you, communicating the quality, colour and attractiveness of a gem is another story.
In response, the lab introduced the Gübelin Gemstone Rating, a system that assigns points to a gem’s overall impression, Raphael Gübelin, president of the House of Gübelin, told National Jeweler.
Knowing that it had to be simple and effective, the laboratory created a comprehensive points-based system inspired by the system used to express the quality of a wine’s vintage.
The Gübelin Gemstone Rating takes into account three factors: quality, rarity and scarcity. The key factor is, of course, quality, which assesses visual aspects such as colour, clarity/transparency and cut. Rarity assesses the type of gemstone, its weight and any treatments used to enhance the gemstone. Finally, salience describes the uniqueness of the gem and its ability to stand out.
Experts in the laboratory use these parameters to calculate a score that communicates the beauty and rarity of a stone in a single number.
High-quality gemstones that score at least 75 out of 100 points qualify for a rating.In addition, gems are given a designation based on their Gübelin point rating: “exceptional” for those scoring 100-97.5; “outstanding” for those scoring 97.4-95; “excellent” for those scoring 94.9-92.5; “superior” for 92.4-90; “fine” for 89.9-85; “good” for 84.9-80; and “fair” for 79.9-75.
The point system will allow the trade to compare coloured gems and assist in buying decisions, the lab says. Currently, if you give someone in the trade a colour and a budget, they can come back with any number of options, Gübelin said.
It would be much more efficient to have additional information that says, ‘I want a blue sapphire, 3 carats, with a nice colour and a rating of 85 or 90. That starts to reduce the number of possibilities enormously. It will help you get much closer to what you’re looking for.It will also help consumers to better understand coloured gemstones.
The laboratory has developed the Gübelin Gemstone Rating for high-quality mined coloured gemstones. Stones that have undergone heavy treatment and lab-grown gemstones fall outside the scope of the rating.Initially, Gübelin will add the service to its reports free of charge.
“The gemstone grading offers more guidance and we think more people will be interested in coloured gemstones,” says Gübelin. “The end consumer will benefit – and of course the industry too.”
After some time, the service will be offered for a fee of CHF 100 (about $110 at current exchange rates) for a gemstone rating in combination with a gemological report.
A rating on its own will cost CHF 250 (about $274), and the lab said it will give ratings to stones with reports from another lab.
The Gübelin Gemstone Rating is currently only available from the company’s laboratory in Lucerne.
