The Diamond Guide

Discover SARAH & SEBASTIAN’s complete guide to natural diamonds - from ethical sourcing and GIA certification to the Four Cs, curated collections, and expert insights.

The Diamond Guide

RESPONSIBLY SOURCED

SARAH & SEBASTIAN has been a certified Responsible Jewellery Council (RJC) member since 2023. This certification followed a rigorous audit against the RJC’s Code of Practices, which covers ethical supply chain management, environmental responsibility, human and labour rights, and transparent product disclosures. It reflects our ongoing commitment to responsible practices, including the ethical sourcing of our natural diamonds and coloured gemstones.

Diamonds

At SARAH & SEBASTIAN, we work exclusively with natural white and champagne diamonds, ranging from Internally Flawless to VS2 clarity, and D to G on the colour scale. We are committed to ethically sourced natural stones of the highest quality and do not offer lab-grown alternatives.

All diamonds are graded by the Gemological Institute of America (GIA), the global authority on diamond certification, and are conflict-free, in accordance with the Kimberley Process.

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THE FOUR C's

Every diamond tells its own story, defined by subtle variations in cut, colour, clarity and carat weight. Known as the Four Cs, these globally recognised standards offer a deeper understanding of a diamond’s quality and beauty.

Explore their significance in our curated Diamond Guide below

cut

Cut and shape are central to how we interpret a diamond’s character. The cut determines how a stone interacts with light, from its brilliance and fire to the subtle flashes of movement. It is often where the design journey begins, as we consider how best to honour the stone’s natural proportions and presence.

At SARAH & SEBASTIAN, we seek out diamonds that are precisely faceted and thoughtfully proportioned, favouring those with GIA cut grades of ‘Excellent’ to ‘Very Good’. Our collection features three distinct cut styles: Brilliant, Step and Mixed. Each is selected for its ability to reveal the unique beauty within the stone. From timeless silhouettes to more distinctive profiles, every cut tells its own quiet story.

Colour

Diamond colour is graded on a scale from D to Z, with D representing the most colourless and rare. The closer a diamond is to colourless, the more extraordinary its beauty and value.

At SARAH & SEBASTIAN, we select only natural diamonds graded between D and G. These range from colourless to near-colourless and are chosen for their refined appearance and luminous clarity.

Clarity

Formed under immense pressure deep within the earth over millions of years, natural diamonds often carry tiny internal features known as inclusions. These markings are a natural part of a diamond’s origin and individuality. Clarity refers to the number, size and placement of these inclusions, with fewer and less visible marks indicating greater rarity and purity.

The GIA grades clarity on a scale from FL (Flawless) to I3 (Included). At SARAH & SEBASTIAN, we select diamonds within the IF (Internally Flawless) to SI1 (Slightly Included) range, with the majority falling between VVS (Very, Very Slightly Included) and VS (Very Slightly Included).

Our in-house gemologists carefully select stones to ensure there are minimal inclusions visible to the naked eye.

Carat

Carat refers to the weight of a diamond, influencing its scale and presence. While larger diamonds are rarer and often more sought after, weight alone doesn’t define a diamond’s true value. It is the relationship between carat, cut, colour and clarity that reveals a stone’s overall beauty.

At SARAH & SEBASTIAN, we consider carat alongside the other three Cs: cut, colour and clarity. This ensures each diamond is selected for its overall beauty, balance and brilliance. We proudly source diamonds in any carat weight above 0.50ct, always within our strict standards for quality and craftsmanship.

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Engagement Experience

The SARAH & SEBASTIAN engagement journey is defined by design, craftsmanship, and a refined, personalised approach. From your initial consultation to the moment your ring is complete and entrusted to you, every detail is considered.

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THE JOURNAL

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