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 31 July 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.

#DiamondOriginScoreLowest Price (GBP)
18.04ct ROUND K SI1natural100£62,232 GBP
28.03ct OVAL G VS2natural100£279,104 GBP
37.03ct CUSHION F VS2natural100£257,756 GBP
47.01ct PEAR I SI2natural100£74,134 GBP
56.06ct OVAL D VVS2lab grown100£11,665 GBP
65.30ct HEART D FLnatural100£171,473 GBP
75.12ct OVAL E VVS2lab grown100£8,164 GBP
85.11ct HEART D IFlab grown100£10,757 GBP
95.06ct OVAL E IFlab grown100£10,651 GBP
105.04ct HEART E IFlab grown100£8,943 GBP
115.01ct ROUND H SI2natural100£39,809 GBP
124.71ct HEART D IFlab grown100£7,215 GBP
134.58ct ASSCHER E VVS2lab grown100£6,634 GBP
144.56ct OVAL D VVS1lab grown100£9,244 GBP
154.24ct ROUND D VVS1lab grown100£3,702 GBP
164.22ct ROUND D VVS1lab grown100£3,685 GBP
174.21ct OVAL D VVS1lab grown100£5,284 GBP
184.16ct HEART D IFlab grown100£6,613 GBP
194.09ct OVAL F VVS2lab grown100£4,441 GBP
204.07ct OVAL D VS1lab grown100£7,001 GBP
214.03ct PRINCESS I VS2natural100£42,940 GBP
224.01ct ROUND J SI1natural100£26,622 GBP
234.01ct ROUND F IFnatural100£119,735 GBP
243.96ct OVAL D FLlab grown100£11,423 GBP
253.91ct OVAL E VS1lab grown100£1,391 GBP
263.79ct ASSCHER D FLlab grown100£11,226 GBP
273.67ct PRINCESS D VVS1lab grown100£3,277 GBP
283.62ct ASSCHER G VVS2lab grown100£543 GBP
293.60ct OVAL E VVS1lab grown100£6,205 GBP
303.57ct HEART D IFlab grown100£4,265 GBP
313.55ct ASSCHER F VS1lab grown100£4,413 GBP
323.52ct OVAL E VS2lab grown100£1,426 GBP
333.52ct OVAL J SI1natural100£24,239 GBP
343.51ct CUSHION E VS2lab grown100£1,394 GBP
353.42ct ROUND E VVS1lab grown100£2,300 GBP
363.37ct PRINCESS E VS2lab grown100£3,992 GBP
373.37ct OVAL E VVS2lab grown100£5,039 GBP
383.33ct RADIANT L VS1natural100£21,854 GBP
393.28ct ROUND F VS1lab grown100£1,033 GBP
403.28ct PRINCESS E VVS2lab grown100£4,886 GBP
413.26ct OVAL E IFlab grown100£3,560 GBP
423.17ct ROUND D VVS1lab grown100£1,655 GBP
433.09ct CUSHION D VVS2lab grown100£2,882 GBP
443.07ct OVAL E VS2lab grown100£976 GBP
453.06ct ROUND E VS1lab grown100£11,398 GBP
463.06ct ROUND D VS2lab grown100£15,270 GBP
473.05ct OVAL E VS2lab grown100£672 GBP
483.05ct OVAL K SI1natural100£16,985 GBP
493.04ct ROUND D VVS1lab grown100£2,135 GBP
503.04ct HEART I SI2natural100£9,685 GBP
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