Diamond Watcher

Diamond Price Index

Latest snapshot: October 2026

Diamond prices vary wildly between retailers for the exact same stone. Every month, we track real listings across major retailers for a fixed set of shapes and carats — so you can see who's actually cheaper, and exactly how much less lab-grown diamonds cost than natural ones.

In October 2026, lab-grown diamonds priced 88% below natural diamonds on average across Ritani, Blue Nile, Rare Carat, and Brilliance. The widest single gap was in 3ct Oval (natural), where Rare Carat ($41,030) undercut Ritani ($52,298) by $11,268.

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Lab-grown vs. natural

88% cheaper
On average, lab-grown diamonds price 88% below natural diamonds of the same shape, carat, color and clarity across Ritani, Blue Nile, Rare Carat, and Brilliance this month.
Shape
Carat
Type

Price grid — shape × carat

Median price, natural diamonds, color G / clarity VS1 — dashed cells are averaged from fewer than 4 retailers

Round$8873/4 retailers$3,419$8,763$19,910$51,157Oval$7513/4 retailers$3,635$9,926$21,116$48,067Cushion$6923/4 retailers$2,085$7,045$15,821$44,7910.5ct1ct1.5ct2ct3ct

Retailer comparison

Round, 1ct, G / VS1, natural

RitaniBlue NileRare CaratBrilliance
Brilliance$2,109● cheapestRare Carat$3,005Ritani$3,948Blue Nile$4,613

Price trend over time

Round, 1ct, G / VS1, natural — median across retailers

$3,000$3,500$4,000AugSepOct

Natural vs. lab-grown premium

How much more natural costs than lab-grown, by shape (1ct, G / VS1)

Round90% cheaper*Oval88% cheaper*Cushion80% cheaper*

* averaged from fewer than 4 retailers on one or both sides

The 1-carat price cliff

Round, natural, G / VS1 — median price by displayed carat weight

Jumping from 0.99ct to 1ct costs $811 more (31%) — despite a barely noticeable size difference. Retailers price by displayed carat weight, not actual weight.

$2,000$4,000$6,0000.9ct0.95ct0.99ct1ct1.01ct1.05ct

Frequently Asked Questions

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Past reports

Median prices from Ritani, Blue Nile, Rare Carat, and Brilliance listings matching each spec. Updated monthly.