How much does a 3.00 to 4.99ct D SI1 lab grown marquise diamond cost?

As of October 2026, 3.00 to 4.99ct D SI1 lab grown marquise diamonds typically cost £306 GBP to £1,522 GBP, with a median price of £662 GBP. There are currently 14 diamonds matching this specification available across retailers.

Where can I find the best price on a D SI1 marquise diamond?

About 46% of these diamonds are available at multiple retailers, with an average price spread of 110%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct D SI1 Lab Grown Marquise

Quick answer

As of October 2026, there are 14 lab grown marquise diamonds with D colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £306 GBP to £1,522 GBP, with a median of £662 GBP. At least 29 retailers stock this exact specification, and 46% of the stones appear at more than one of them, with an average price spread of 110%. Half of all listings fall between £182 GBP and £526 GBP per carat. The same specification in natural form lists at a median of about £15,179 GBP per carat. Over the last 30 days the median price moved +21.7% and the number of listings moved +65.7%.

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. Marquise lab grown stones in the index: 485 USD per carat, -3.2% 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

Lowest Price

£264 GBP

Highest Price

£3,710 GBP

Average Price

£892 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

45.6%

Price Spread

109.8%

30-Day Price Trend

+21.7%

30-Day Supply Change

+65.7%

Volatility (30d)

0.07

Price Range

Price per carat distribution across retailers

$417/ct

10th Percentile

$140

Median

$417

90th Percentile

$1,183

Score Distribution

23 diamonds scored across 4 quality tiers

Excellent

11 (47.8%)

Very Good

3 (13.0%)

Good

3 (13.0%)

Average

6 (26.1%)

Find Your Diamond

Search 14 D SI1 marquise diamonds and compare prices.

Search Diamonds

Consider Instead

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

D SI2SI2 inclusions are not visible without magnification

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