First, thank you for your efforts in creating this site. It is an incredible perspective in a market that is otherwise lacking reason-based analysis accessible to the consumer. I don’t have a way to validate your methods, but your approach seems very sound. If you could definitively validate this, it really has the potential to disrupt the entire market.
My question — As a typical consumer, why should I care whether a diamond is GIA certified (as opposed to a lesser lab)?
It seems like I would be using the following info to assess a diamond:
- reliable high-quality 3D video of the diamond
- diamond’s dimensions (from a lab report)
- DiamondScreener’s algorithm results
If I can make a good assessment based on that, then why would I care which lab created the report? Who cares if a certain lab is more lax on their cut/quality/color definitions? In 2019 the diamond’s symmetry/cut/sparkle is visible online (in insane detail) by both myself, as well as your algorithm. So I would really be disregarding the lab assessment anyway! Right now even the GIA triple-excellent category gets parsed apart. So why is it even relevant?
To me, it seems that the GIA was valuable in the pre-internet (and maybe pre-DiamondScreener) era, when otherwise you had to trust a salesman in a store (ie, the information was highly asymmetric between seller and consumer). In that era, the GIA report was used as assurance that a diamond at least cleared a certain standard.
But now, it seems that the only thing I’m really getting from that report is the diamond dimensions. I assume that all labs (GIA or not) report this truthfully – is that accurate?
Am I missing something? Or am I witnessing the impending upheaval of an industry? I’m not trying to be dramatic, just buying a ring for my girl. But the entire current structure just seems obsolete.
In the past, you would go into a jewelry store, look at their limited selection, and buy a diamond that looked good to you. The grading report might corroborate what you saw. Keep in mind, GIA cut grades weren’t introduced until 2005, so your eye was the only way to evaluate cut.
Then buying diamonds online became possible. For a long time, large websites like Blue Nile did not have pictures of diamonds on their site. The grading report took on a greater significance because that’s the only information that was available.
Now, photography is good enough to evaluate a diamond online. The visual appearance should take precedence again. The information on the grading report can help you narrow down the thousands of options to a manageable number and corroborate what you see, but it shouldn’t be the primary driver of the decision.
All labs can provide objective information such as diamond proportions – those are read by machine. GIA actually provides the least precision on their reports – they round their crown angles to the nearest 0.5 and their pavilion angles to the nearest even number.
Now to your question. If you already know how to judge diamonds, then it shouldn’t matter if a diamond is GIA certified or not. If you can evaluate cut, color, and inclusions on your own, then you know what you’re getting and can tell whether or not it’s a good deal.
However, the operative phrase in your question is “if I can make a good assessment based on that”. Most people buying an engagement ring have never bought a diamond before. Even if you provide all of that information – 3D video, dimensions, guidelines for cut quality – they don’t know how to interpret it. A GIA grading report is the only consistent standard they have for comparison.
The grading report is just a starting point. It won’t tell you if the I color is H or closer to J, if the I is yellow, brown or gray, or if the SI1 is eye-clean or not. These are things you need to check visually.