Proud Winners of Independent Retailer of the Year & Overall Business of the Year 2022

We understand that finding the perfect engagement ring can be a daunting experience, however, at L. Guess our knowledgeable and friendly team can take the time to expertly guide you through the process, with our extensive ranges of beautiful engagement rings across both of our Rustington and Littlehampton stores. We offer a wide range to suit individual styles and budgets.

If you’re looking to express your love in a completely unique way, our bespoke design service may be the perfect fit for you, with our team able to inspire you to select the perfect Gemological Institute of America (GIA) certificated diamond or coloured gemstone.

If diamonds aren’t your style we can also offer beautiful coloured gemstones, handcrafted or pre-owned and vintage rings which could be the perfect match to say ‘yes’ to. Visit us in-store or book a personalised appointment to speak to a member of our friendly and professional team.

Diamond Advice

Diamond Advice

Your options in terms of setting style, cut, carat and material are endless, which doesn’t make for an easy decision. To assist in making the ideal choice of diamond we have outlined the main 4C focus points when choosing ‘the one’…

The Gemological Institute of America (GIA) grade diamonds against the 4Cs of diamond quality: Colour, Clarity, Cut and Carat Weight. GIA created this standard, along with the scientific procedures for evaluating each “C” and the grading terminology used to describe them.

The 4C’s provide a way to objectively compare and evaluate diamonds. But numbers alone can’t describe a diamond’s captivating beauty – visit us in-store or book a personalised appointment to find the perfect stone.

Click on each number below to find out more



Colour grades are determined by comparing each diamond to a master set. Each GIA colour scale letter grade represents a range of colour from D (colourless) and Z (light yellow or brown) – this is a measure of how noticeable a colour is.

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The GIA clarity scale includes eleven clarity grades ranging from Flawless to I3. Because diamonds form under tremendous heat and pressure, it is extremely rare to find a diamond that lacks any internal and external characteristics. These characteristics are a by-product of its formation and help gemologists separate natural diamonds from synthetics, and identify individual stones.

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The GIA Cut Scale ranges from Excellent to Poor. A polished diamond’s beauty lies in its complex relationship with light. The magnificent display you see is made up of three attributes…

  • Brightness – this is the combination of all white light reflecting from the surface and interior of a diamond.
  • Fire – this describes the ‘flares’ of colour emitted from a diamond.
  • Scintillation – this describes the pattern of light and dark areas and the sparkle you see when the diamond, the light, or the observer moves.

A diamond’s proportions affect its light performance, which in turn affects its beauty and overall appeal. Diamonds with fine proportions, symmetry, and polish optimise their interaction with light, and have increased brightness, fire and scintillation.

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Carat Weight

One carat equals 200 milligrams in weight. For diamonds under one carat, each carat is divided into 100 points – similar to pennies in a pound. 0.75ct = 75 points. 1/2 ct. = 50 points.

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“I had a bespoke ring made by L. Guess Jewellers using my own stones. They designed and produced an amazing signet ring which exceeded my expectations..”