Grown Diamond Comparison Guide

Choosing a stone for your engagement ring or fine jewelry means understanding what is actually inside it. This guide compares grown diamonds against the other stones you are most likely to encounter while shopping: mined diamonds, moissanite and cubic zirconia.

Grown Diamonds Vs. Diamond Simulants Vs. Mined Diamonds: What's The Difference?

A grown diamond is pure crystallized carbon, grown in a controlled laboratory environment. It shares the same chemical, physical and optical properties as an earth-mined diamond and is graded on the same scale. Diamond simulants are created to mimic the look of a diamond but contain no diamond carbon at all. Cubic zirconia and moissanite are the two most common simulants.

PropertiesGrown diamondCubic zirconiaMined diamondMoissanite
% of diamond carbon bonds100%0%100%0%
Mohs hardness108.0 - 8.5109.25
Refractive index2.422.15 - 2.182.422.65 - 2.69
OriginLaboratoryLaboratoryEarthLaboratory
DurabilityExceptionalModerateExceptionalVery high
Typical priceModerateLowestHighestLower

Note: pricing shifts often. The figures above are directional.

Grown Diamond Vs. Cubic Zirconia

Cubic zirconia has been a common diamond alternative for decades: a manufactured zirconium oxide crystal designed to mimic a diamond's sparkle at a much lower price. It contains no diamond carbon, is noticeably softer, and is more prone to scratching and clouding over time.

PropertiesGrown diamondCubic zirconiaSummary
% of diamond carbon bonds100%0%Grown diamonds are pure carbon. CZ contains no diamond.
Mohs hardness108.0 - 8.5CZ is softer and shows wear sooner.
Refractive index2.422.15 - 2.18CZ looks glassier next to a diamond.
ClarityGraded VS to SIUsually flawlessOnly the diamond is graded on the diamond scale.

Grown Diamond Vs. Mined Diamond

Grown and mined diamonds are the same material. The difference is origin, and often price.

PropertiesGrown diamondMined diamondSummary
CompositionPure carbonPure carbonChemically identical.
Mohs hardness1010Equally durable.
OriginLaboratoryEarthGrown diamonds have a known origin.
Typical priceLowerHigherGrown diamonds cost less for the same grade.

Grown Diamond Vs. Moissanite

Moissanite is silicon carbide, a different material with its own fire. It is harder than most gemstones but softer than diamond, and it shows more colored flashes of light.

PropertiesGrown diamondMoissaniteSummary
CompositionCarbonSilicon carbideDifferent materials.
Mohs hardness109.25Both are very durable.
Refractive index2.422.65 - 2.69Moissanite shows more rainbow flashes.
Typical priceModerateLowerMoissanite costs less.