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GCAL Certificate Decoder, find a redacted GCAL report number

Find a hidden GCAL report number using just the specs you can see, a partial number, or a scan of the cert PDF. GCAL grades optical performance and offers an 8X cut tier. Free, instant, no signup.

No retailer pays us a cent. No affiliate kickbacks. No paid rankings. We match your specs against millions of certified diamonds at 100+ retailers worldwide.
Fast lookup

Have a cert number? Look it up here.

Paste a GIA, IGI, HRD, AGS, or GCAL report number to see every retailer in our index carrying the same diamond, with live prices side by side.

Do not have the cert number, or the retailer redacted it? Use the spec matcher below to recover it from the visible 4Cs and measurements.

18.4M
Diamonds tracked
9.76M
Active
8.63M
Sold or off-market
Have a cert image or PDF?
Drop a cert PDF or image here
click to choose, or paste from clipboard (Ctrl/Cmd+V): PDF, PNG, JPEG, WEBP, max 10 MB
18,392,314
Enter your specs to begin
Core specs
Origin
Shape
Carat
Colour
Clarity
Partial certificate number (visible digits)
If the retailer redacts part of the cert number, enter just the digits you can see (first few, last few, or any visible portion). We will substring-match against our index.

How it works

Every grading report records a precise combination of carat, colour, clarity, cut, polish, symmetry, fluorescence and measurements. That combination is unique enough that a few specs narrow your match to one stone in our index of millions of certified diamonds. Add what you can see on the retailer's listing, and the live counter shows how many stones still match. When the counter hits one, the certificate number is yours.

Scan or upload a diamond certificate

Drop a GIA, IGI, HRD, AGS, or GCAL cert PDF or photo onto the upload area at the top of the page. Our OCR engine reads the report number, 4Cs and measurements automatically and runs the match for you. You can drag and drop, click to choose a file, paste an image straight from your clipboard with Ctrl or Cmd plus V, or open the camera on your phone and snap the cert directly. We accept PDF, PNG, JPEG and WEBP up to 10 MB. The file is processed in a sandboxed worker and never stored, never shared.

Verify or look up a diamond report number

If you already know the report number, paste it into the certificate field and the decoder confirms whether the diamond is in our index, lists every retailer carrying it, and shows the live price spread. If you have only part of the number visible, paste the visible digits into the partial certificate field and combine them with the visible 4Cs to narrow down. The same flow works as a cross-check against the lab's own report verification tool when the listing's printed number looks suspect.

Compare the same diamond across retailers

Once the decoder identifies the cert number, click through to the diamond detail page. We show every retailer in our index that lists the same physical stone, side by side, with current prices and price history. The same diamond often appears at 5 to 20 retailers and price spreads of 30 to 80 percent are normal, especially on lab grown stones. The cert decoder is the first step. The diamond detail page is where the price comparison happens.

Why some retailers hide the certificate number

Retailers redact the certificate number because manually finding the same physical stone elsewhere is genuinely hard. There is no central public index that maps cert numbers to all the retailers carrying them. To do it by hand a buyer would have to know which retailers might stock that stone (most buyers know two or three names, the supply network is over a hundred), search each one (most retailer search tools do not accept GIA or IGI numbers as a query), interpret regional pricing, and re-check over the days a purchase decision takes. The redaction works because the friction stops most buyers from trying. That is also why aggregator tools like this one exist: doing the cross-retailer lookup manually across more than a hundred retailers is impractical, but it is exactly the kind of pattern matching a database can do in milliseconds.

Frequently asked questions

How do I look up a GIA report number?
Enter the specs visible on the retailer's listing: shape, carat, colour and clarity. The live counter narrows the match as you add attributes. Add cut, polish, symmetry, fluorescence and measurements as you have them. With three measurements (length, width, depth in millimetres) plus the 4Cs, the match almost always narrows to a single GIA-graded diamond and the report number is revealed. The same flow works for IGI, HRD, AGS and GCAL reports.
Can I scan or upload a diamond certificate image or PDF?
Yes. Drop a cert PDF or photo onto the upload area at the top of this page, paste an image from your clipboard with Ctrl or Cmd plus V, or open your phone camera and snap the cert directly. The OCR engine extracts the report number, 4Cs and measurements automatically and runs the match. Supports GIA, IGI, HRD, AGS and GCAL reports. Files are processed in a sandboxed worker, never stored, never shared.
Where is the report number printed on a diamond certificate?
On a full GIA grading report the report number sits in the top right of the header next to the report date. On a GIA Dossier (the smaller pocket format) it appears on the front page above the diamond's 4Cs. IGI prints the report number on the front of the laser-inscription panel and on the QR code at the bottom. HRD and AGS use a similar header position. The number is always 8 to 13 digits.
How do I find the same diamond at another retailer?
Once the decoder identifies a cert number, click through to the diamond detail page. We show every retailer in our index carrying that exact cert with live prices side by side. The same physical stone often appears at 5 to 20 retailers and price spreads of 30 to 80 percent are common. Our index covers more than 100 retailers across natural and lab grown inventory, refreshed continuously.
What if the retailer hides most of the cert number?
Use the partial certificate field. Enter just the digits you can see, whether they are the first few, the last few, or any visible portion. The matcher uses substring search alongside the 4Cs and measurements. Two or three visible digits combined with shape, carat, colour, clarity and one measurement usually narrow the candidates to a single stone.
Why would a retailer hide the certificate number?
Manual cross-retailer comparison is genuinely hard. There is no central public index linking cert numbers to all retailers carrying them, retailer search tools rarely accept GIA or IGI numbers as input, and the supply network covers over a hundred retailers most buyers have never heard of. Redacting the cert number works because the friction stops most buyers from trying. Hiding the number protects the retailer's margin by keeping the comparison work out of reach.
Does this work for IGI, HRD, and AGS as well as GIA?
Yes. Pick the lab tab at the top of the form. Each lab has its own page (gia-decoder, igi-decoder, hrd-decoder, ags-decoder) with the same matching engine and lab-specific guidance.
What if I do not have all the specs?
Start with what you have. The match counter narrows as you add attributes. If you have measurements (length, width, depth), enter them. Three measurements plus carat plus colour plus clarity will usually narrow to a single match.
Is this tool free?
Yes. No signup, no card, no email. The decoder is free for any visitor.
Are you affiliated with GIA, IGI, HRD, AGS or GCAL?
No. Carat Hunter is independent and is not affiliated with, endorsed by, or sponsored by any grading laboratory. Reference to those marks is for identification and comparison purposes only.
Independent comparison tool. Not affiliated with GIA, IGI, HRD, AGS or GCAL. Listings reflect data observed from public retailer pages. Verify final price and availability with the retailer before purchase.