Gemstones are minerals which have been created deep underground and when cut, cleaned up and polished can be used to create many different items of jewellery and adornments.
Most gemstones are very durable and their rarity is a characteristic which adds such high value to them. In ancient cultures gemstones were owned by the upper class and indicated a certain social status.
Corundum is a tough mineral which is known for its gem varieties, ruby and sapphire. They are both the same mineral however ruby is the red variety and sapphire is the variety that holds all other colours. However the most renowned and popular colour for the sapphire is blue and one that most people recognise. Beryl is also a rock forming mineral which is colourless in its purest form. The rocks impurities cause the variation of colours, ‘emeralds’ describe the green variety.
Find out more about three of the most popular gemstones: Rubies, Emeralds, and Sapphires
FACTORS AFFECTING THE VALUE OF THE PRECIOUS STONES:
Gems can be found holding many different colors. When discussing the colour of a gemstone, three factors need to be taken into account: hue, saturation and tone. A Sapphire is renowned for its blue colour. However due to the many different hues, you can also find sapphires in a variety of colours, for example pink and yellow.
Generally the brighter the stone, the higher the value. A medium toned stone is the most sought after and desirable. The perfect colour for an emerald is described as ‘grassy green’ and for a sapphire, ‘cornflower blue’. Both of these colours hold a medium tone, not too dark and not too light.
The number of inclusions found in a gemstone affects its clarity. Inclusions are formed when the stone is created in the earth. They can be used by some gemmologists to determine the origin of the stone and therefore inclusions are often referred to as the stones birthmark.
Generally the fewer the inclusions, the more valuable the stones are as they are quite rare. However in some cases, inclusions are responsible for increasing the value of a stone, for example a cat’s eye emerald.
Inclusions tend to have more of an impact on paler stones as they are much easier to see.
Gemstones are sold by their weight. The measurement of one carat = one fifth of a gram. It is generally quite rare to find large gemstones particularly regarding sapphires, emeralds and rubies. These are generally priced higher than smaller stones (unless distinguished by other factors for example clarity, cut and colour.)
Each gem reflects light differently. When discussing cut, two factors are taken into account. One factor is the 3-dimensional shape created for example round brilliant, oval, pear. The second factor is the quality of the cut. For example ideal, deep or shallow cut. The best cut is symmetrical and allows light to reflect across the whole surface of the gem with no dark areas.