Sterling Jewellers
diamond rings
Browse our full collection of fine jewellery — handcrafted in gold and silver with free UK delivery.
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Diamond Rings: Understanding the 4 Cs
Buying a diamond ring is a significant investment, and understanding the 4 Cs — Cut, Colour, Clarity and Carat — will help you get the best diamond for your budget.
Cut is the most important factor. A well-cut diamond reflects light beautifully and appears larger and more brilliant than a poorly cut stone of the same carat weight. Our diamonds are graded Excellent or Very Good cut by the GIA.
Colour is graded on a scale from D (completely colourless) to Z (noticeable yellow tint). For engagement rings, we recommend stones in the D–H range for a bright, white appearance. I–J stones offer excellent value and appear white to the naked eye when mounted in white metal.
Clarity refers to the presence of inclusions (internal) or blemishes (surface). Grades range from Flawless to Included. For the best balance of beauty and value, VS1–VS2 (Very Slightly Included) stones are ideal — any inclusions are invisible to the naked eye.
Carat is a measure of weight (1 carat = 0.2 grams), not size. Two diamonds of the same carat weight can appear very different depending on cut quality. A well-cut 0.90ct round brilliant will often appear larger than a poorly cut 1.00ct stone.
Frequently Asked Questions
What is the difference between GIA and IGI certified diamonds?+
The GIA (Gemological Institute of America) is widely considered the most stringent grading laboratory. IGI (International Gemological Institute) is equally trusted and is the primary certifier for lab-grown diamonds. Both provide reliable and detailed grading reports.
Are lab-grown diamonds real diamonds?+
Yes. Lab-grown diamonds are chemically, physically and optically identical to mined diamonds. They are graded by the same criteria (4 Cs) and certified by the same laboratories. They typically cost 50–70% less than equivalent natural diamonds.
GIA & IGI Certified
Every diamond graded
Handcrafted in UK
Master craftsmen
30-Day Returns
No questions asked
Lifetime Warranty
Free servicing