How much does a 1.50 to 1.99ct H SI1 natural cushion diamond cost?

As of October 2026, 1.50 to 1.99ct H SI1 natural cushion diamonds typically cost £2,660 GBP to £7,059 GBP, with a median price of £4,475 GBP. There are currently 470 diamonds matching this specification available across retailers.

Where can I find the best price on a H SI1 cushion diamond?

About 34% of these diamonds are available at multiple retailers, with an average price spread of 55%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct H SI1 Natural Cushion

Quick answer

As of October 2026, there are 470 natural cushion diamonds with H colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £2,660 GBP to £7,059 GBP, with a median of £4,475 GBP. At least 63 retailers stock this exact specification, and 34% of the stones appear at more than one of them, with an average price spread of 55%. Half of all listings fall between £2,129 GBP and £3,655 GBP per carat. The same specification in lab grown form lists at a median of about £462 GBP per carat. Over the last 30 days the median price moved -1.8% and the number of listings moved +7.7%.

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. Cushion natural stones in the index: 2,948 USD per carat, +1.7% 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

470

Lowest Price

£1,554 GBP

Highest Price

£14,726 GBP

Average Price

£4,722 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

34.1%

Price Spread

54.9%

30-Day Price Trend

-1.8%

30-Day Supply Change

+7.7%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$3,727/ct

10th Percentile

$2,317

Median

$3,727

90th Percentile

$6,106

Score Distribution

1.2K diamonds scored across 4 quality tiers

Excellent

156 (12.8%)

Very Good

230 (18.9%)

Good

324 (26.6%)

Average

506 (41.6%)

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Consider Instead

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

H SI2SI2 inclusions are not visible without magnification

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Lab-Grown H SI1Same specifications, lab-grown origin

Save 83%

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