Know if your diamond is
Upload a photo or book a lab test and get a clear, expert-backed verdict on authenticity, carat, cut and clarity — in minutes, not weeks. No jeweller markup, no guesswork, no subscriptions.
Upload a photo — test your diamond now
Our gemologist-trained AI reads brilliance, fire and facet geometry to screen real diamond from moissanite, cubic zirconia and glass. One to four angles, an instant verdict.
Upload Diamond Photos
Multi-angle analysis
Tap to upload photos
0/4 photos · any format → auto WebP · max 10MB
📷 For best results, capture these angles:
Diamond Profile
Photograph each labelled part for the most accurate AI read.
The cheap pen lies. We don’t.
A $20 tester checks heat — and moissanite passes it every time. Diamonds Tester reads the optical, electrical and structural tells that actually separate real, lab-grown and fake.
Gemologist-trained, not guesswork
Every model decision is benchmarked against GIA-graded reference stones and reviewed by certified gemologists.
Simulants don’t slip through
Moissanite passes cheap diamond pens. We screen for thermal, optical and electrical tells those pens miss entirely.
You own the report
Download a clean PDF for insurance, resale or your own records — yours forever, no subscription required.
Privacy by default
Your photos and stones are never shared or sold. Lab samples are tracked and insured end to end.
Pick your level of certainty
From a free instant photo screen to an insurance-ready lab certificate — choose what your stone deserves.
Photo Verification
FreeA first-pass verdict in under a minute.
Upload sharp photos of your stone — table, profile and girdle. Our gemologist-trained model reads facet geometry, light return and surface tells to flag whether it behaves like a natural diamond, a lab-grown, or a simulant such as moissanite or cubic zirconia.
- Instant brilliance & dispersion read
- Moissanite / CZ simulant screening
- Facet symmetry & cut-grade hints
- Shareable PDF summary
Lab Certification
from $79Independent, gradeable, insurance-ready.
Ship your stone to our partner laboratory for instrument testing — thermal and electrical conductivity, refractive index, UV fluorescence and spectroscopy. You receive a numbered certificate covering the full 4Cs, origin (natural vs. lab-grown) and a plotted clarity map.
- Conductivity + spectroscopy testing
- Full 4C grading report
- Natural vs. lab-grown origin call
- Tamper-proof numbered certificate
Mail-in Testing
from $39Insured, tracked, back in your hands fast.
Prefer a quick verdict without full certification? Send your piece in our insured, tamper-evident mailer. A certified gemologist tests it by hand and returns a concise authenticity report — typically within three business days of arrival.
- Prepaid insured shipping label
- Hand-tested by a certified gemologist
- Authenticity + estimated value
- 3-day average turnaround
Four steps to a clear verdict
Snap or send
Upload well-lit photos from your phone, or request an insured mailer for hands-on lab testing. No appointment, no jeweller markup.
We test
Our model and gemologists read brilliance, dispersion, facet geometry and — for lab tests — conductivity and spectroscopy to separate natural, lab-grown and simulant.
Clear verdict
You get a plain-English result: real, lab-grown or fake, with confidence, the 4Cs where measurable, and an estimated market value.
Certify & protect
Upgrade to a numbered certificate for insurance, resale or peace of mind — recognised by jewellers and insurers worldwide.
Four tips for a sharper read
The AI is only as good as your photos. A minute of care here makes the difference between a confident verdict and an inconclusive one.
Light it well
Shoot in bright, indirect daylight. Avoid hard flash — it blows out the brilliance and fire we read.
Clean it first
A quick wipe removes skin oil and dust that dull sparkle and hide inclusions from the camera.
Capture 3 angles
Top (table down), side profile, and straight through the table. More angles, sharper verdict.
Get close & steady
Fill the frame, tap to focus, keep a plain dark background. Macro mode if your phone has it.
The tells you can see for yourself
At-home checks rule out obvious fakes — but they can’t separate diamond from moissanite, or natural from lab-grown. That’s where we come in.
Take the real-vs-fake quizFog test
Real: Clears almost instantly — diamond disperses heat fast.
Fake: Stays fogged for a few seconds (glass, CZ).
Sparkle (brilliance vs. fire)
Real: Grey-white brilliance with crisp rainbow flashes.
Fake: Moissanite throws excessive, almost disco-like rainbow fire.
Heat / conductivity probe
Real: Diamond conducts heat exceptionally — passes a thermal tester.
Fake: Moissanite also passes heat pens — needs an electrical tester too.
Reflections (read-through)
Real: You can’t read newsprint through a properly cut diamond.
Fake: Glass and quartz let text show through clearly.
What actually moves the value
Cut
How well the diamond returns light.
Cut is the only C controlled by human hands and the biggest driver of sparkle. We assess proportions, symmetry and polish to estimate where a stone falls from Excellent to Poor.
Colour
How close to colourless it is.
Graded D (colourless) to Z (light yellow). The difference between neighbouring grades is subtle but moves price sharply — we benchmark against master stones.
Clarity
Inclusions and surface blemishes.
From Flawless to Included (I3). We map inclusions and note whether they’re eye-clean — the practical question most buyers actually care about.
Carat
The diamond’s weight, not its size.
One carat is 0.20 grams. Because price jumps at round weights, a 0.90ct can be far better value than a 1.00ct that looks identical face-up.
Explore diamond guides
Real, gemologist-written guides on testing, the 4Cs, cuts, certificates, pricing and care — everything you need before you buy, sell or insure.
The clearer way to know for sure
| Diamonds Tester | High-street jeweller | $20 tester pen | Guesswork | |
|---|---|---|---|---|
| Instant photo verdict | — | — | — | |
| Catches moissanite | ~ | — | — | |
| Natural vs. lab-grown call | £££ | — | — | |
| Insurance-ready certificate | — | — | ||
| No sales pressure / unbiased | — | |||
| Cost to start | Free | Appointment | ~$20 | Free |
| Time to an answer | < 1 min | Days–weeks | Seconds | — |
Straight answers, earned trust
"Inherited my grandmother’s ring and had no paperwork. Diamonds Tester confirmed it was a natural 1.2ct and the certificate got it insured the same week."
"The photo check flagged my “diamond” as moissanite in under a minute. Saved me from overpaying a private seller by thousands."
"As a small jeweller I use the mail-in service for estate pieces. Fast, insured, and the reports are genuinely trusted by my buyers."
"Clear, honest, no upselling. They told me my stone was lab-grown and still worth keeping. That kind of straight answer earns trust."
"Inherited my grandmother’s ring and had no paperwork. Diamonds Tester confirmed it was a natural 1.2ct and the certificate got it insured the same week."
"The photo check flagged my “diamond” as moissanite in under a minute. Saved me from overpaying a private seller by thousands."
"As a small jeweller I use the mail-in service for estate pieces. Fast, insured, and the reports are genuinely trusted by my buyers."
"Clear, honest, no upselling. They told me my stone was lab-grown and still worth keeping. That kind of straight answer earns trust."
Learn before you buy
A photo screen is a guide, not gospel
We’d rather tell you the truth than oversell a verdict. Here’s exactly where an instant photo test stops — and why a lab test takes over.
A photo can flag simulants, but can’t separate a natural diamond from a lab-grown one — that needs spectroscopy.
Lighting and image quality change what the camera sees, so confidence varies with your photos.
A tight setting can hide the girdle, culet and inclusions we rely on for the closest read.
For insurance, resale or a legal record, always confirm a photo screen with an instrument-based lab test.
Stop wondering. Know for certain.
Free photo screening, expert lab certification, zero subscriptions. Your verdict is minutes away.