Lucy's Diamond Insights
Deep market analysis, price trends, and diamond buying intelligence from Lucy, our resident diamond market analyst.
Subscribe via RSSThe Ideal cut illusion: how 5.97 million round listings show 42 percent of IGI lab rounds carry an Ideal tier label that GIA does not issue
The diamond trade's standard buyer advice is to demand a Triple Excellent finish on a round brilliant: Excellent cut, Excellent polish, Excellent symmetry.
The round tax inverts in lab grown: how 921,467 matched-spec listings show round is the most expensive natural shape and the cheapest lab shape
The diamond trade has long described round brilliants as the most expensive shape per carat.
How to Verify Any Diamond Certificate Online for Free
Every major diamond lab offers free online certificate verification. GIA, IGI, and HRD all maintain public tools that return a stone's grading data in seconds. Skipping this step means trusting the retailer's listing on faith alone.
The carat cliff: 0.99ct diamonds are 166 times rarer than 1.00ct in 2 million round listings, and the gap explains why your jeweller never offered you a 0.97
The diamond trade has long known that cutters round to magic-number weights at 0.90, 0.95, 1.00, 1.50, and 2.00ct.
Why Some Jewellers Hide Certificate Numbers, and How to Find Them Anyway
When a jeweller hides a diamond's certificate number, they're hiding your ability to comparison shop. Our cross-retailer data shows the same certified stone can vary by 20% to 70% depending on where you buy it. That spread represents thousands of dollars on an average purchase.
Decode HRD and AGS Certificate Numbers, the Less Common Labs
HRD and AGS certificate numbers follow patterns that most diamond buyers never learn, until a confusing listing forces the issue. Our decoder handles both labs, including the tricky cases where an eight digit number could be an HRD cert or a retailer SKU.
GIA does not grade cut on fancy shapes: what 2.8 million reports reveal about the industry's invisible convention
GIA assigns an overall cut grade to one shape only.
Decode an IGI Certificate Number, the Lab-Grown Specific Guide
IGI grades more lab-grown diamonds than any other lab, but inconsistent report number formatting and high production volume make cert decoding trickier than you'd expect. We walk through the nine digit format, the disappearing LG prefix, and a worked example narrowing a 2ct E VVS2 oval to a single match.
Decode a GIA Certificate Number From Specifications Alone
Every GIA graded diamond has a unique ten digit certificate number, and you can reverse engineer it from the specs alone. This guide walks through the exact narrowing process, from shape and carat down to measurements, using a real worked example.
The fluorescence discount is not flat: how 395,554 GIA listings show the price hit running from -23 percent on D to zero on H Medium
Conventional buying advice treats fluorescence as a single-direction penalty: avoid Medium and Strong fluorescence to dodge a price discount.
How to Find a Diamond Certificate Number When the Retailer Has Hidden It
Retailers who hide the certificate number are betting you won't do the research. Our 16 million diamond database can identify almost any stone from its grading specs alone, turning a redacted listing into a fully traceable diamond.
The lab-natural price gap is not 70 percent: what 1.5 million listings reveal about how the spread widens with carat
Industry shorthand says lab-grown diamonds are 70% to 80% cheaper than natural at matched specs.