The Diamond Merchant
Exceptional Diamonds. Complete Transparency.
The world's most complete free diamond education resource — search our live inventory by Stock ID or certificate number.
Diamond Tools
Nine professional-grade calculators, completely free, with no sign-up required.
Diamond Size Comparison
Visualise carat weight against your hand — before you buy.
Open Tool 02Ring Size Converter
Translate between US, UK, EU and circumference in millimetres.
Open Tool 03Ratio Calculator
Length-to-width ratio with ideal-range guidance per shape.
Open Tool 04Spread Calculator
Estimate face-up diameter from carat weight alone.
Open Tool 05Price Estimator
Ballpark market range from the 4Cs — for education, not valuation.
Open Tool 06Certificate Checker
Verify any GIA, IGI or AGS report number instantly.
Open Tool 07Jewellery Calculator
Estimate total piece cost: diamond + metal + labour.
Open Tool 08Gold Weight & Melt
Convert metal weight to troy oz and current melt value.
Open Tool 09Carat Calculator
Estimate carat from millimetre measurements using GIA formulas.
Open ToolDiamond Education
Everything you need to understand, compare, and select the perfect diamond.
Understanding the 4Cs
Cut, colour, clarity and carat — the universal language of diamond value.
Read GuideDiamond Shapes
From the timeless round to the dramatic marquise — every shape explained.
Read GuideLab vs Natural
The complete unbiased comparison of lab-grown and earth-mined diamonds.
Read GuideDiamond Certification
GIA, IGI, AGS — what grading reports mean and how to read them.
Read GuideThe Buying Guide
A step-by-step framework to buy the right diamond with confidence.
Read GuideDiamond Anatomy
Table, crown, girdle, pavilion — the parts that make a diamond perform.
Read Guide