How to Buy Diamonds with Confidence

Everything you need to know to find the perfect diamond for you. At Biagio's the Jewellers, we can find you the perfect stone at a price that suits your pocket.

All diamonds are precious and those possessing the highest quality of cut, colour, clarity and carat weight (the four Cs) are the rarest and most valuable, but we believe there is a fifth C - confidence. Confidence in the source and craftsmanship of the diamond. This is as important as the essence of the stone itself.


Diamond necklace, £1,414.00


As the supreme gemstone, the diamond owes its name to the Greek adamas, meaning invincible. Invincible for the power believed to be granted to the wearer; invincible for being the hardest mineral known to man; and invincible for its brilliance.

Diamonds were created almost 80 million years ago, when pipe-shaped accumulations were pushed upwards at huge speed from inside the earth by a series of violent explosions, creating conditions favourable to the crystallisation of diamonds from whatever carbon was available. 

Diamonds have been used in jewellery from very early days, but it wasn’t until diamond cutting was developed in the late 17th century that their beauty was revealed. The brilliant cut, today’s standard cut, has 58 facets, their size and shape and the angles between them intricately calculated to create both internal and external reflecting and refractive surfaces, with the aim of providing the maximum brilliance. 

Did you know? 

  • Diamond is the birthstone for April.
  • Diamonds were thought by the Greeks to protect the wearer from evil particularly if they were worn on the left-hand side.
  • It is thought that early inhabitants of South Africa used diamonds to etch their famous rock engravings.
  • Although diamonds are mostly colourless, they can be found in any number of delicate shades.
  • Only about 20% of diamonds mined are suitable for gemstones, and during the cutting process, these lose more than half their weight.
  • Diamonds are traditionally given on a 60th wedding anniversary. 


Round brilliant diamond ring, £1,785.00


Of the four Cs, Cut is the only one of the four Cs influenced by man.

There are many different types of cuts to choose from; a good, round brilliant cut releases the life and sparkle of a diamond through the arrangement and proportion of its 57 or 58 facets. Light reflects from facet to facet and disperses through the top of the stone, creating a display of brilliance.


While most diamonds appear white, many display hints of colour barely discernible to the naked eye. The closer a diamond approaches colourlessness, the rarer and more valuable the stone.

Diamonds with a strong pure colour are extremely rare and are called ‘fancies’. Amongst them can be found pink, blue, green, orange, yellow and even black. The rarest are blue and pink.

The scale defined by the European Gemological Laboratory (EGL) is divided into steps between D and Z, D being the clearest and most valuable:D-E: exceptional white; F-G: rare white; H: white; I-J: slightly tinted white; K-L: tinted white; M-Z: tinted colour. 


A diamond’s clarity is determined by the degree to which it is free from naturally occurring inclusions, often called ‘nature’s fingertips’. The number, type, colour, size and position of the internal birthmarks can affect a diamond’s value, however, many are invisible to the naked eye and require magnification under a standard 10x magnification loupe. The fewer inclusions, the rarer the stone.

The EGL Scale of Clarity refers to the amount of inclusion in a stone when viewed through a 10x magnification loupe. FL/IF equals flawless or internally flawless, VVS1 and VVS2 very, very slightly included, VS1 and VS2 are very slightly included, SI1 and SI2 slightly included, I1, I2 and I3 are included.



18ct princess cut diamond halo ring, £4,100.00


Carat refers to weight and therefore the size of the diamond. One carat is divided into 100 points. A diamond weighing 50 points equals half a carat. Two diamonds of equal size can have very different values, depending on their cut, clarity and colour.

All diamonds are precious and those possessing the highest quality of cut, colour, clarity and carat weight (the four Cs) are the rarest and most valuable. 

The Fifth C - Confidence:

Established for over 30 years, we work hard to make sure our customers can feel absolutely confident with their diamond purchases. We pride ourselves on a personalised service delivered by our friendly team of diamond and jewellery experts and we believe the more you know, the better equipped you are to make the right decision

Along with offering our wedding rings and diamond engagement rings collections, we source loose diamonds to help customers create any bespoke design.

Rigorous quality checks are carried out throughout every phase of design and manufacturing to achieve complete customer satisfaction. We also are members of The National Association of Jewellers, who iare commited to ensuring that every NAJ member abides by the NAJ’s Code of Conduct, which based on honesty, integrity and professionalism, so you can gain peace of mind and confidence by purchasing from your diamonds from Biagio the Jewellers.