A Guide to Gemstones in Jewellery


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Gemstones are those wonderfully precious stones that when cut and polished just right, can make a piece of jewellery sparkle like no other! Below is a guide to the most well known gemstones used in jewellery.



By kallerna (Own work) [CC-BY-SA-3.0 or GFDL], via Wikimedia Commons
By kallerna (Own work) [CC-BY-SA-3.0 or GFDL], via Wikimedia Commons
Diamonds are made from carbon, and formed in a structure that makes them among the hardest materials on earth. Due to the structure of the atoms which make impurities very rare, diamonds have fantastic optical qualities allowing them to disperse lots of light. Diamonds are valued by their cut, clarity, colour and carat.  These unique qualities lead to the fantastic sparkle that make diamonds so desirable in high end jewellery, such as diamond engagement rings .




Natural pearls occur in the pearl oysters in the wild, and are the most sort after and expensive pearls. Pearls come in different shapes, but the most valuable are perfectly round and smooth and are very rare.  Natural pearls are made up of lots of layers of calcium carbonate. The thinner and more numerous the layers are, the more fragile and better the refracting and reflecting light the pearl is. And hence more valuable. The rareness of pearls has made them a beautiful base for fine jewellery, such as a pearl necklace and pearl earrings.



Rubies come from a mineral called corundum and are second only to diamonds in hardenss among gemstones. Similarly to diamonds, the four C’s – cut, colour, clarity and carat – contribute towards value as well as geographic location. However a lot more importance is placed on colour, with the brighter the red of the ruby commanding a higher price. A certain grading of red must be met for it to be called a ruby, otherwise it may be classified as a pink sapphire.



By Andrew Bossi from Laurel, MD, USA [CC-BY-SA-2.0], via Wikimedia Commons
By Andrew Bossi from Laurel, MD, USA [CC-BY-SA-2.0], via Wikimedia Commons
Like rubies, sapphires come from the mineral corundum. The difference in the other trace elements of minerals which lead to a variety of colours, most commonly blue and green. In fact all colour of gemstones coming from corundum are classified as sapphires, except for those which are red, which are of course rubies. As with rubies, their value is determined by the four C’s.




Faceted emerald gemstones
Faceted emerald gemstones (Photo credit: Wikipedia)


Emeralds come from the mineral beryl, and are of green colour. They are quite soft in comparison to other gemstones due to them being much more inclusions (imperfections) than other stones. Due to the rareness of emeralds having no surface inclusions, most are treated to enhance clarity. As with other gemstones value is determined by the four C’s.




Opal is the natural gemstone of Australia, which produces 97% of the world’s opals.  Opals are created from silica that can occur in the fissures of any kind of rock. The thing that makes opals precious and quite beautiful to behold is their ability to diffract light, and not just white light, they have the ability to express every colour in the visible spectrum, giving the opal a unique place in as a gemstone used in precious jewellery.



There are numerous other categories of gemstone that are less common and valued in pieces of jewellery.  Whatever your preferred style of jewellery, the above gemstones make a beautiful addition to any piece.


Bio: Jonathan is the owner of Libertons, an online jewellery marketplace that specialises in a variety of gemstone jewellery.