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Gemologist vs Diamond Grader

In our introduction of diamonds, we mentioned Diamonds Graders extensively. We have customers asking what does Diamond Graders/Diamond Professionals/Graduate Diamond Professional mean in comparison to a Gemologist. Here we will explain the difference so that you would know what the advice you receive from your jeweller is based on.

*Diamond Graders/Diamond Professionals/Graduate Diamond Professional are people who completed the Graduate Diamonds course, to simplify it, I will just call them Professional Diamond Graders. They are not people who actually work in laboratories and grade diamonds for a living.

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To begin, Gemology is the study of gemstones, which also is a sub study of Geology. Gemstones refer to stones with value that can be used for jewellery purposes. In the world, there are many schools that offer the study of Gemology, which upon completion, you would be accredited as a Graduate Gemologist. GIA, the Gemological Institute of America is the most prestigious and widely recognized gemology course in the world - also known as an Harvard school equivalent of Gemology Education. Any trade member who would like a good foundation in the industry would undergo the GIA Graduate Gemologist course, just like how we at Moltenore Fine Jewellery Atelier did.

So in the process to be a Graduate Gemologist, it would take on about a year (half a year if you are fast), to complete all the sub courses which comes in various difficulties. And the Graduate Diamonds course, is just one of the sub courses to take. In the following table, I have explained the difference based on our experience.

Based on the courses taken, it is apparent that a Professional Diamond Grader learns a fraction of what a Gemologist did. Yes, Professional Diamond Graders are well equipped to help you with any of your diamond queries, but so are gemologists. In fact, a gemologist would be even more well versed as they would have a wider and deeper range of knowledge. As what the title Professional Diamond Grader suggest, they are taught to grade a diamond, but this does not extend to physically testing if the stone is truly a diamond or if it has been treated.

Instead, as part of the Graduate Gemologist course, gemologists are taught to differentiate between diamond simulants (look alikes) such as synthetic mossanite, synthetic rutile, colourless sapphire, cubic zirconia, YAG etc.. This practical skill is not taught in the Graduates Diamond Course. So while some jewellers or even a Professional Diamond Grader may that a simulant looks exactly like a diamond, bear in mind that there are many gemologists that can actually tell the difference. Often, with just a loupe or with our eyes.

What about Synthetics?

The same thing goes. A gemologist has slightly more knowledge than a Professional Diamond Grader in this aspect. Many Professional Diamond Graders would theoretically know the difference between a HPHT Diamond and a CVD Diamond, but will not be able to tell them apart. Actually, given how well created synthetic diamonds are, a gemologist may also have difficulty but is trained to use gemstone testing equipment to identify patterns and differentiate them.

HPHT - High Pressure High Temperature

CVD - Carbon Vapour Diamonds

Diamonds created in the CVD process however may need advanced testing equipment that is only available in certain special laboratories. For HPHT diamonds, some gemologists may be able to identify them with just a loupe due to their oddly hazy appearance, which looks different compared to the cloudy appearance from fluorescence. However, this is also based on experience.


Depending on the kind of gemstone that you are looking for, it is important to seek the right people for advice. At Moltenore, we are a house of Graduate Gemologists experienced in valuation, appraisal at auction levels and have seen countless rare investment gemstones. Have a question about gemstones? Please feel free to contact us.


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