
A Guide to Diamonds
The name ‘diamond’ refers to its hardness (Greek – adamas, the unconquerable). Billions of years ago, deep within the earth, elemental forces of intense heat and pressure miraculously transformed carbon into diamond. Despite being known gemstone, a diamond is surprisingly simple in composition.
Diamonds are evaluated based on four key criteria, known as the 4 Cs: cut, colour, clarity and carat weight. At Jan Logan, we adhere to the Gemological Institute of America’s (GIA) International Diamond Grading System, ensuring that each piece meets the highest standards of quality and excellence.
Our diamonds are sourced from family-owned companies that share our commitment to safeguarding the environment and human rights. Every larger diamond we offer is accompanied by a GIA certificate, recognised globally as the leading authority on diamond grading. Additionally, all our suppliers comply with the Kimberley Process, which aims to eliminate conflict diamonds from the global supply chain.
Of all the 4 Cs, cut is the one most directly influenced by craftsman skill. It is the most important factor when choosing a diamond. A well-executed cut enhances the diamond’s ability to reflect light, maximising its brilliance and scintillation. At Jan Logan, the cut of each diamond is observed carefully by our specialists to promise the beauty and sparkle our clients expect to see.
Colour quality is critical in diamond. The whiter and more colourless a diamond is, the more extraordinary its beauty and value are. The GIA’s grading system measures the variety of colour from D (colourless and white) to Z (light yellow). At Jan Logan, we recommend diamonds coloured from F to H, guaranteeing both whiteness and value.
The unique nature of diamonds often results in ‘inclusions’ which are often not discernible to the naked eye. The degree and intensity of these ‘inclusions’ informs the clarity and value of the diamond – fewer ‘inclusions’ makes the diamond more valuable.
‘Inclusions’ are ranked on a scale of perfection from F (flawless) to I (included). At Jan Logan we recommend a VS (very slightly included) to SI (slightly included) clarity to assure the quality and uniqueness of each stone.
The weight of a diamond, measured in carats, refers to the physical size of the diamond. While it is the most obvious feature to determine the value of a diamond, the overall cost is dependent upon all of the 4 Cs.
The shape and design of the diamond is significant in determining the look and feel of a ring. All Jan Logan stones, no matter their shape, have been cut to reflect the maximum amount of light and sparkle with unique brilliance.
To ensure customers arrive at the best combination of cut, colour, clarity and carat that suits their style and taste, our staff at Jan Logan have extensive experience and knowledge to assist you.

The Bespoke Process
Begin your journey by scheduling a consultation with our team, where we’ll discuss your vision and preferences in detail. Through elevated designs, we will ensure your unique vision & individuality are meticulously crafted into an exquisite reality.
Collaborate closely with our expert designers, jewellers, and gemmologists to craft a bespoke design that embodies your unique style and desires. In this stage, our expert team will guide you through sketches, 3D renders and material elements to finesse your final design.
Experience the culmination of your vision as we meticulously bring your custom piece to life, ensuring it is a true reflection of your personal taste and craftsmanship.

Craftmanship & Responsible Sourcing
At the heart of our sustainability mission lies a dedication to shaping an innovative future with minimal environmental impact. Jan Logan exclusively sources materials that come with certifications verifying their adherence to ethical, human rights, social, and environmental standards, ensuring sustainability throughout our supply chain. At Jan Logan, we take immense pride in having crafted our own jewellery for over 35 years. Our highly skilled team of jewellers - setters, polishers, and stringers - are driven by a shared pursuit of excellence, perfection and unmatched quality.