How much does a 1.50 to 1.99ct F SI1 natural round diamond cost?

As of October 2026, 1.50 to 1.99ct F SI1 natural round diamonds typically cost £4,602 GBP to £12,931 GBP, with a median price of £7,392 GBP. There are currently 1,029 diamonds matching this specification available across retailers.

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

About 39% of these diamonds are available at multiple retailers, with an average price spread of 44%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct F SI1 Natural Round

Quick answer

As of October 2026, there are 1,029 natural round diamonds with F colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £4,602 GBP to £12,931 GBP, with a median of £7,392 GBP. At least 69 retailers stock this exact specification, and 39% of the stones appear at more than one of them, with an average price spread of 44%. Half of all listings fall between £3,739 GBP and £5,779 GBP per carat. The same specification in lab grown form lists at a median of about £286 GBP per carat. Over the last 30 days the median price moved -1.9% and the number of listings moved +15.4%.

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

1,029

Lowest Price

£1,611 GBP

Highest Price

£20,589 GBP

Average Price

£8,152 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

38.6%

Price Spread

44.4%

30-Day Price Trend

-1.9%

30-Day Supply Change

+15.4%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$6,108/ct

10th Percentile

$4,159

Median

$6,108

90th Percentile

$9,540

Score Distribution

2.5K diamonds scored across 4 quality tiers

Excellent

307 (12.3%)

Very Good

685 (27.4%)

Good

540 (21.6%)

Average

966 (38.7%)

Find Your Diamond

Search 1,029 F SI1 round diamonds and compare prices.

Search Diamonds

Consider Instead

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

F SI2SI2 inclusions are not visible without magnification

Save 33%

Lab-Grown F SI1Same specifications, lab-grown origin

Save 94%

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