How much does a 0.75 to 0.99ct J SI1 natural round diamond cost?

As of October 2026, 0.75 to 0.99ct J SI1 natural round diamonds typically cost £692 GBP to £1,946 GBP, with a median price of £1,072 GBP. There are currently 1,141 diamonds matching this specification available across retailers.

Where can I find the best price on a J SI1 round diamond?

About 40% of these diamonds are available at multiple retailers, with an average price spread of 53%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct J SI1 Natural Round

Quick answer

As of October 2026, there are 1,141 natural round diamonds with J colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £692 GBP to £1,946 GBP, with a median of £1,072 GBP. At least 61 retailers stock this exact specification, and 40% of the stones appear at more than one of them, with an average price spread of 53%. Half of all listings fall between £955 GBP and £1,583 GBP per carat. The same specification in lab grown form lists at a median of about £921 GBP per carat. Over the last 30 days the median price moved -2.6% and the number of listings moved +15.6%.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, September 2026: natural diamonds at 2,335 USD per carat and lab-grown at 443 USD per carat, a natural to lab ratio of 5.3 to 1. Round natural stones in the index: 2,248 USD per carat, +7.6% month on month. See the full index release

Figures come from current listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: October 2026

Available

1,141

Lowest Price

£317 GBP

Highest Price

£3,274 GBP

Average Price

£1,215 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

39.9%

Price Spread

53.3%

30-Day Price Trend

-2.6%

30-Day Supply Change

+15.6%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,564/ct

10th Percentile

$1,087

Median

$1,564

90th Percentile

$3,158

Score Distribution

2.8K diamonds scored across 4 quality tiers

Excellent

444 (16.1%)

Very Good

703 (25.5%)

Good

607 (22.0%)

Average

1,002 (36.4%)

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Consider Instead

Save money without compromising on what matters. These alternatives are visually similar but cost less.

J SI2SI2 inclusions are not visible without magnification

Save 9%

Lab-Grown J SI1Same specifications, lab-grown origin

Save 22%

Related Specifications

D IF D VVS1 D VVS2 D VS1 D VS2 D SI1 E IF E VVS1 E VVS2 E VS1 E VS2 E SI1 F IF F VVS1 F VVS2 F VS1 F VS2 F SI1 G IF G VVS1 G VVS2 G VS1 G VS2 G SI1 H IF H VVS1 H VVS2 H VS1 H VS2 H SI1 I IF I VVS1 I VVS2 I VS1 I VS2 I SI1