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 £2,662 GBP to £7,122 GBP, with a median price of £4,523 GBP. There are currently 495 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 495 natural cushion diamonds with H colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £2,662 GBP to £7,122 GBP, with a median of £4,523 GBP. At least 62 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 £2,144 GBP and £3,684 GBP per carat. The same specification in lab grown form lists at a median of about £466 GBP per carat. Over the last 30 days the median price moved -1.8% and the number of listings moved +7.8%.

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

495

Lowest Price

£1,567 GBP

Highest Price

£14,849 GBP

Average Price

£4,767 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

33.8%

Price Spread

55.0%

30-Day Price Trend

-1.8%

30-Day Supply Change

+7.8%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$3,719/ct

10th Percentile

$2,312

Median

$3,719

90th Percentile

$6,104

Score Distribution

1.3K diamonds scored across 4 quality tiers

Excellent

167 (12.5%)

Very Good

261 (19.6%)

Good

374 (28.1%)

Average

530 (39.8%)

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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