Sitemap
Calculators
- Gemstone mm to Carat Calculator: Estimate carat weight from length, width and depth for any common cut and gem.
- Carat to mm Size Finder: See how big a stone of a given carat weight will look, with a to-scale outline.
- Carat to Gram Converter: Convert carats, points, grams, grains, pennyweights and ounces both ways.
- Diamond Equivalent Weight Calculator: Compare real weight and size across diamond, moissanite, CZ and colored stones.
- Total Carat Weight Calculator: Add up center stones, halos and melee into one total carat weight.
- Price per Carat Calculator: Turn a price per carat into a total, with discount and tax.
Size charts
- Diamond Size Chart in mm: Round and fancy shape diamond sizes from 0.05 to 5 carats.
- Moissanite Size Chart: Millimetre sizes with both diamond equivalent and real weight.
- Moissanite vs Diamond Size: Why a 1 carat moissanite and a 1 carat diamond are not the same size.
- Lab-Grown vs Natural Diamond Size: Same material, same density, same size per carat.
- Sapphire Carat to mm Chart: Dense corundum, so smaller per carat than diamond.
- Ruby Carat to mm Chart: Ruby size by carat for round, oval and cushion cuts.
- Emerald Carat to mm Chart: Light beryl, so larger per carat than diamond.
- Amethyst Carat to mm Chart: Quartz sizes, a big look for the weight.
- Topaz Carat to mm Chart: Almost exactly the density of diamond.
- Garnet Carat to mm Chart: Almandine sizes, with notes on other garnets.
- Aquamarine Carat to mm Chart: A light beryl that faces up large.
- Spinel Carat to mm Chart: Between diamond and sapphire in size per carat.
- Cubic Zirconia Carat to mm Chart: Very dense, so much smaller than a diamond of the same weight.
Guides
- What Is a Carat?: Weight, points, and why carat is not size.
- Why the Same Carat Weight Looks Different: Density, shape, depth and girdle explained with worked examples.
- How to Measure a Gemstone: Using calipers or a gauge, step by step, for every shape.
- How to Estimate Gem Weight in a Setting: A full worked example and an honest error budget.
- Gemstone Specific Gravity Chart: Density for 29 gem materials, with ranges and sources.
- How We Calculate: Every formula, constant, source and limit we use.