Top 50 Diamonds by Certification Score in United Kingdom
Ranked by certificate rigour. GIA and AGS stones with complete grading, clear symmetry, and verified provenance come out on top. Pricing shown in GBP.
Last updated 15 September 2026 · Based on 50 active listings ranked by certification
What Certification Score Rewards
Certification score measures the rigour and completeness of the grading report behind each diamond. It weights the grading lab (GIA and AGS lead; IGI and HRD follow; newer or less-consistent labs are lower), the presence of a polish and symmetry grade (required for Excellent-cut claims), and the completeness of the proportions data. It's not measuring the diamond itself. It's measuring how confident you can be that the grades on paper match what you'll receive.
Use this list when you're buying at a price point where certification rigour matters most. Say, above $10,000, or when the stone will be insured, resold, or given as a gift with a certificate presentation. The top of this list is where the paper trail is strongest: full GIA reports with polish and symmetry grades, complete measurement data, and a clean provenance.
A high certification score doesn't mean the stone is beautiful. It just means the grading is trustworthy. Cross-reference with quality score for stones that are both well-documented and well-made. For lab-grown, IGI tops this list more often than GIA because IGI has become the default lab-grown certifier and has the most complete reports for that segment.
| # | Diamond | Origin | Score | Lowest Price (GBP) |
|---|---|---|---|---|
| 1 | 8.04ct ROUND K SI1 | natural | 100 | £91,671 GBP |
| 2 | 8.03ct OVAL G VS2 | natural | 100 | £290,504 GBP |
| 3 | 7.03ct CUSHION F VS2 | natural | 100 | £220,947 GBP |
| 4 | 7.01ct PEAR I SI2 | natural | 100 | £66,338 GBP |
| 5 | 5.30ct CUSHION D FL | natural | 100 | £141,558 GBP |
| 6 | 5.12ct OVAL E VVS2 | lab grown | 100 | £7,654 GBP |
| 7 | 5.11ct HEART D IF | lab grown | 100 | £10,123 GBP |
| 8 | 5.06ct OVAL E IF | lab grown | 100 | £10,024 GBP |
| 9 | 5.04ct HEART E IF | lab grown | 100 | £8,416 GBP |
| 10 | 5.02ct OVAL H SI1 | natural | 100 | £80,951 GBP |
| 11 | 5.01ct ROUND H SI2 | natural | 100 | £34,128 GBP |
| 12 | 5.01ct CUSHION G SI1 | natural | 100 | £48,285 GBP |
| 13 | 4.71ct HEART D IF | lab grown | 100 | £6,790 GBP |
| 14 | 4.56ct OVAL D VVS1 | lab grown | 100 | £8,700 GBP |
| 15 | 4.50ct ROUND H VVS1 | natural | 100 | £28,101 GBP |
| 16 | 4.24ct ROUND D VVS1 | lab grown | 100 | £3,470 GBP |
| 17 | 4.22ct ROUND D VVS1 | lab grown | 100 | £3,127 GBP |
| 18 | 4.21ct OVAL D VVS1 | lab grown | 100 | £4,973 GBP |
| 19 | 4.16ct HEART D IF | lab grown | 100 | £6,223 GBP |
| 20 | 4.07ct OVAL H VVS2 | natural | 100 | £52,373 GBP |
| 21 | 4.03ct PRINCESS I VS2 | natural | 100 | £37,170 GBP |
| 22 | 4.03ct HEART E VS2 | natural | 100 | £59,457 GBP |
| 23 | 4.02ct HEART H SI1 | natural | 100 | £29,478 GBP |
| 24 | 4.01ct ROUND J SI1 | natural | 100 | £22,165 GBP |
| 25 | 4.01ct ROUND H SI2 | natural | 100 | £24,877 GBP |
| 26 | 3.96ct OVAL D FL | lab grown | 100 | £10,070 GBP |
| 27 | 3.91ct OVAL E VS1 | lab grown | 100 | £979 GBP |
| 28 | 3.79ct ASSCHER D FL | lab grown | 100 | £9,616 GBP |
| 29 | 3.67ct PRINCESS D VVS1 | lab grown | 100 | £3,084 GBP |
| 30 | 3.62ct ASSCHER G VVS2 | lab grown | 100 | £1,648 GBP |
| 31 | 3.60ct OVAL E VVS1 | lab grown | 100 | £5,839 GBP |
| 32 | 3.57ct HEART D IF | lab grown | 100 | £4,013 GBP |
| 33 | 3.52ct OVAL E VS2 | lab grown | 100 | £4,928 GBP |
| 34 | 3.52ct OVAL J SI1 | natural | 100 | £22,336 GBP |
| 35 | 3.51ct MARQUISE E VS2 | lab grown | 100 | £1,312 GBP |
| 36 | 3.42ct ROUND E VVS1 | lab grown | 100 | £1,923 GBP |
| 37 | 3.33ct ASSCHER L VS1 | natural | 100 | £16,761 GBP |
| 38 | 3.28ct ROUND F VS1 | lab grown | 100 | £527 GBP |
| 39 | 3.28ct PRINCESS E VVS2 | lab grown | 100 | £5,521 GBP |
| 40 | 3.26ct OVAL E IF | lab grown | 100 | £3,350 GBP |
| 41 | 3.17ct ROUND D VVS1 | lab grown | 100 | £734 GBP |
| 42 | 3.10ct HEART I SI2 | natural | 100 | £9,367 GBP |
| 43 | 3.09ct CUSHION D VVS2 | lab grown | 100 | £2,121 GBP |
| 44 | 3.08ct OVAL G VS1 | lab grown | 100 | £1,625 GBP |
| 45 | 3.07ct OVAL E VS2 | lab grown | 100 | £920 GBP |
| 46 | 3.07ct OVAL G VS1 | lab grown | 100 | £1,556 GBP |
| 47 | 3.05ct OVAL E VS2 | lab grown | 100 | £917 GBP |
| 48 | 3.05ct OVAL K SI1 | natural | 100 | £13,028 GBP |
| 49 | 3.04ct ROUND D VVS1 | lab grown | 100 | £1,882 GBP |
| 50 | 3.04ct HEART I SI2 | natural | 100 | £8,359 GBP |
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