Customer service

Diamond Knowledge

With a wide range of wedding rings available as well as its own dedicated diamond jewellery collection, diamonds sparkle brightest at T H Baker. We recognise that it can get confusing for shoppers on the lookout for diamonds, with so much information and sales pitches being volunteered.

That's why we hope to simplify the process and enlighten diamond devotees to the 4 C's: the worldwide characteristics used to classify the rarity, quality and value of diamonds.

Carat ('ct')

The carat of gold used in a piece of jewellery is illustrated in its hallmark, and has two separate meanings:

1) It is the unit of weight measurement for gemstones, whereby one carat is equal to one-fifth of a gram. A carat is divided into 100 points, with 25 points being equal to ¼ carat.

2) It describes the purity of gold alloy used in an item of jewellery. Pure gold is rated as 24 carat, with the following representing the most common standards of gold alloy used in jewellery:

  • ct gold, 37.5% pure gold (or 375 parts pure gold and 625 parts other metals)
  • 4ct gold, 58.5% pure gold (or 585 parts pure gold to 415 parts other metals)
  • 8ct gold, 75% pure gold (or 750 parts pure gold and 250 parts other metals)
  • 2ct gold, 91.6% pure gold (or 916 parts pure gold and 84 parts other metals)


The clarity of a diamond is gauged by the degree to which it is free from naturally occurring inclusions, or "nature's fingerprints". Such "birthmarks" can affect the value of the diamond overall, depending on their number, type, colour, size and position. However, many of these inclusions are actually invisible to the naked eye and require a closer look under an eyeglass to be seen. Diamond aficionados should be aware that the fewer the inclusions, the rarer the diamond is and, in conclusion, more valuable.

Against all of our diamonds you are able to choose which clarity we have available. Here is a table outlining the grades of clarity and what to expect.

Clarity Meaning
F Flawless
IF Internally Flawless
VVS1-VVS2 Very Very Slightly Included 1 and 2
SI1-SI2 Slightly Included 1 and 2
I1-I2-I3 Included 1, 2 and 3


Although most diamonds appear white, many actually display hints of colour barely visible to the naked eye. The closer a diamond is to colourless, the rarer and more valuable it is. Colours that may be found within a diamond include pink, blue, yellow, green and orange. Diamonds that possess a strong pure colour are extremely rare and are often referred to as "fancies".

To help you decide which colour you would prefer, here is a guide for the different industry grades.

D – F - Diamonds with this grade are the nearest to pure, and are the most valuable.

G – I - Have virtually no colour that is visible to the untrained eye.

J – M - Have a warmer, more yellow tone that many people prefer, benefiting from a more vintage aesthetic.


The cut of the diamond is the only value-defining characteristic of the 4 C's that can be influenced by man. Poor cutting can severely decrease the value of a diamond. When a diamond is cut so that all the facets are in proportion, light will reflect from one facet to another and disperse through the top of the stone, resulting in a rich display of brilliant light. Alternatively, when a diamond's facets are not in proportion or it is cut too shallow or deep, then the light is not reflected and refracted adequately which results in a less brilliant display. The style of the diamond cut (such as baguette, emerald or marquise) is a matter of personal taste and is not as great a factor in influencing a diamond's value.

  • Ideal cut (This cut only applies to round diamonds.)
  • Fine cut
  • Shallow cut
  • Deep cut