Diamond guide

A lab-grown diamond is the same material as a natural one: crystalline carbon, the same hardness (10 on the Mohs scale), the same brilliance and the same optical properties. The difference is origin — a natural diamond formed deep in the earth over millions of years, a grown one in a laboratory over a few weeks. Without instruments they cannot be told apart.

At the same weight and quality a grown stone costs several times less, which lets you choose a larger or cleaner stone for the same budget. A natural diamond is rare and is traditionally seen as holding value. Both are graded by the same laboratories — IGI and GIA — and the certificate states the origin either way.

In the site's configurator a grown stone is chosen by parameters — cut, weight from 0.5 to 4 carats, quality — and is always available. A natural stone is a specific piece: it is chosen in the Nanea Diamonds section, with its own photo and certificate.

1. 1

   Carat — weight

   One carat is 0.2 grams. Weight is the most visible characteristic, but stones of the same weight can look different in size depending on the cut and its proportions. A round 1-carat stone is about 6.4 mm across.

2. 2

   Color

   Colourless diamonds are graded from D (fully colourless) to Z (noticeably yellowish). D–F are colourless, G–J near-colourless; once set, G–H cannot be told from D by eye. In yellow and rose gold a faint tint shows less than in white.

3. 3

   Clarity

   The absence of internal inclusions and surface blemishes, from FL/IF down to I3. In VS1–VS2 and above, inclusions are invisible to the naked eye; SI1 is often eye-clean too, but look at the photo.

4. 4

   Cut

   Cut quality decides how much light the stone returns. It is graded from Excellent to Poor. We recommend Excellent and Very Good first — cut affects sparkle more than colour or clarity. A separate cut grade exists only for round stones.

The site offers thirteen cuts: round, oval, marquise, pear, emerald, Asscher, cushion, elongated cushion, heart, radiant, princess, trillion and baguette. Round returns the most light; elongated shapes (oval, marquise, pear) look larger at the same weight and lengthen the finger; step cuts (emerald, Asscher) show the clarity of the stone and call for a higher clarity grade.

A certificate is an independent laboratory report confirming the stone's weight, colour, clarity, cut, measurements and origin. GIA (Gemological Institute of America) and IGI (International Gemological Institute) are the most recognised laboratories in the world; IGI in particular grades most lab-grown stones. The report number can be checked on the laboratory's website, and on many stones it is laser-inscribed on the girdle.

At nanea the centre stone comes with a laboratory certificate. Every stone in the Nanea Diamonds section is already certified by IGI or GIA, and the stone's page shows a photo of that very stone, often a 360° view and the certificate itself.

A stone's price rises in steps, not in a straight line: 1.00 ct costs noticeably more than 0.90 ct although the difference is invisible. On a limited budget, pick a weight just under the round numbers, an Excellent cut, G–H colour and VS2–SI1 clarity — the stone will sparkle the most and the money goes to what the eye can see.

In the Nanea Diamonds section the price of each stone is final — in drams, including 20% VAT, with no hidden markups. Ordered with a ring, the stone's price is added to the setting's price and the stone's delivery days to the lead time. The stone is brought to Yerevan, checked at the workshop and only then set.

• Nanea Diamonds: pick a real stone
• Engagement rings
• How to order