Guides & expertise · Diamantaires OG
Expertise & appraisal of your GIA diamond
Since 1985, our family-run business has been appraising and purchasing diamonds and jewelry at 43 rue Beaubourg, in Paris 3ᵉ. The appraisal is conducted in your presence by a state-certified gemologist: it is free of charge, with no appointment necessary and no obligation.
The Gemological Institute of America (GIA) is the global benchmark for diamond certification. Each graded stone receives a unique certificate number, most often laser-inscribed on the girdle, which can be viewed publicly in the GIA database. A GIA-certified diamond therefore has better resale value: its characteristics are attested, verifiable and indisputable.
We purchase your GIA-certified diamonds from 1 carat: the appraisal is free, the offer is firm and payment is immediate. We also appraise diamonds certified by IGI, HRD or EGL — and stones without a certificate.
How it works
The appraisal in three steps
Present your diamond
Without an appointment at 43 rue Beaubourg (Paris 3ᵉ), or remotely: photo via WhatsApp, form or phone — with or without a certificate.
Gemological analysis
A state-certified gemologist examines your stone’s 4Cs and verifies its certificate directly in the laboratory database (GIA, IGI, HRD…).
Firm offer, immediate payment
You receive a firm offer at market price. If a competitor has made you a direct offer, we match it and exceed it.
The 4Cs: how your diamond is evaluated
The GIA defined the global diamond grading standard, applied by highly qualified gemologists. After analysis, the stone is delivered in a sealed container, its certificate number laser-inscribed on the girdle.
Weight (Carat)
Weight is measured in carats — 1 carat = 0.20 gram — on a high-precision scale. All else being equal, the price per carat increases in steps: our price guides detail values from 0.5 to 5 carats.
Color
For colorless to tinted diamonds, color is graded from D to Z. Fancy-colored diamonds follow their own scale based on hue, saturation and uniformity — see our color guide.
Clarity
Clarity describes the nature, number and location of inclusions. The scale ranges from flawless — FL (Flawless), then IF (Internally Flawless) — to I3: VVS1 and VVS2, VS1 and VS2, SI1 and SI2, then I1, I2 and I3, diamonds referred to as “piqué” and graded P1 to P3 in the European nomenclature. For a complete laboratory analysis, the stone must be unmounted and perfectly cleaned. See our VVS clarity guide.
Cut
Cut is evaluated based on proportions (relationships between crown, pavilion, total height and diameter), symmetry and polish, graded from Excellent to Poor. Dimensions are expressed in millimeters.
The certificate also mentions fluorescence — the stone’s reaction to ultraviolet light, graded from None to Very Strong —, indicates any treatments and confirms that the diamond is natural and not synthetic. To understand each section of the report, consult our GIA certificate guide.
To learn more
Certificates, prices and quality
The GIA certificate decoded
Grading report, proportions, laser inscription: understanding each section of your certificate.
View the guide →
Prices per carat
From 0.5 to 5 carats: current price benchmarks to gauge the value of your diamond.
View the guide →
The 4Cs in detail
Color, clarity, cut, carat: the criteria that determine a diamond’s quality — and price.
View the guide →Free, no-obligation appraisal
How much is your diamond worth?
Appraisal by a state-certified gemologist — firm offer, immediate payment.
All Our Diamond Guides
All our guides, written by the house, to understand certification, assess a stone's quality and determine its price.
Laboratories & certificates
- ◆ The GIA certificate decoded
- ◆ What is the GIA?
- ◆ The IGI laboratory
- ◆ Selling an HRD diamond
- ◆ Evaluating an EGL diamond
- ◆ French gemology laboratories
- ◆ SCAN or CIBJO certified diamonds
- ◆ Getting your diamond certified
Evaluating your diamond
- ◆ The 4Cs of diamond quality
- ◆ Diamond color
- ◆ VVS clarity
- ◆ Diamond shapes
- ◆ Determining a diamond's weight
Price per carat
Frequently Asked Questions
Diamond appraisal in practice
How can I get a free appraisal for my GIA certified diamond?+
Call us at 01 48 87 23 37, visit us without an appointment at 43 rue Beaubourg 75003 Paris, or describe your stone using the form on this page: a state-certified gemologist will respond within 24 hours.
What guarantee do you offer on buying a GIA diamond?+
We guarantee the best purchase terms: if you have a direct purchase offer from a competitor, we will match it and commit to providing a higher bid.
What are the GIA's diamond grading criteria?+
The GIA grades each diamond according to the 4Cs: Color, Clarity, Cut, and Carat weight. Each stone receives a unique certificate number, publicly verifiable in the GIA database.
Why does GIA certification add value to a diamond?+
The Gemological Institute of America is the worldwide standard for certification: a diamond that has passed its rigorous inspections sells better, as its characteristics are attested and verifiable by all.
What are the hours for an in-store appraisal?+
Monday to Friday from 10 a.m. to 1 p.m. and from 2 p.m. to 6:30 p.m., at 43 rue Beaubourg 75003 Paris (M° Rambuteau), with or without an appointment.
Do you also sell diamonds and jewelry?+
Yes — our boutique offers certified diamonds and signed jewelry selected by the house, to be discovered online or at 43 rue Beaubourg.
Can I get a remote pre-appraisal before coming in?+
Yes: send a photo via WhatsApp or describe your stone by email ([email protected]) or via the form — you will receive an initial evaluation, then refined in-store, in your presence.
Free Appraisal
Get your diamond appraised
Describe your stone — with or without a certificate — or simply send a photo via WhatsApp. Your request remains strictly confidential.
- ◆ Response within 24 hours from a state-certified gemologist
- ◆ Free and without obligation
- ◆ Firm offer, immediate payment in-store