Guide to Coloured Gemstones & Diamonds

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Coloured Gemstones

Gemstones come in many varied colours due to the chemical compounds they contain & it is for this reason that they also display different physical characteristics such as hardness, refractability & transparency.

Many gemstones have only ever been discovered in one place for example Tanzanite, hence they are extremely rare & valuable for this reason. Such gemstones are in limited supply, for example supplies of Tanzanite are predicted to expire in 15 years time at most, making them a worthwhile investment. 

Some gemstones display stunning colour effects for example Alexandrite which is praised for its colour changing properties (pleochromism) or Cat's Eye (which contains horizontal fibres that reflect light in a linear fashion giving them the appearance of a cat's eye hence the name).

It is for such reasons that gemstones have been used in jewellery pieces to adorn the body, given as tokens of love or simply admired for thousands of years, & have attracted the ideas of possession of mystical or spiritual powers hence the existence of birthstones.

This guide aims to give you a brief overview of the most commonly used & most popular gemstones found in jewellery today.


The most well known & most commonly used of all the gemstones. Diamond is praised for its amazing return of light (brilliance & fire) & its extreme hardness. Diamond takes its name from the Greek word 'adamas' meaning invincible. It has been used as a symbol of eternal love for thousands of years & is the classic gem to be set in any Engagement or Eternity ring. Diamond is also the birthstone of April.


Emerald is known for its deep green colour & is part of the Beryl family of gemstones which also includes Aquamarine. It takes its deep green colour from Chromium & Vanadium. Emerald is said to have been the favourite gemstone of Cleopatra with the most beautiful Emeralds being found previously in Greece but now in Colombia (South America). Emerald is hard to find without growth charasteristics (inclusions) known as 'Jardins' in Emerald, after the French word for garden due to the its deep green colour. It is one of the only gemstones appreciated for featuring inclusions, as with Emerald this adds to the gems beauty. Emerald is a brittle gemstone therefore must be protected against harsh knocks. It is for this reason the 'Emerald (Rectangle) Cut' was invented as it meant the gemstone was less likely to become cleaved during cutting & later wear. This cut is very popular today & now often used for Diamonds also.


Sapphire is the birthstone of September & is popular for its common deep blue colour which is due to iron & titanium. Sapphire (the corundum gemstone family) can be found in most colours ranging from yellow to red (known as ruby) with Pink Sapphire becoming very popular lately also. Sapphire is historically been symbolic of faithfullness & chastity (hence its wear in most religious jewellery/costume & in the Crown Jewels) & so has been popular for many years in Engagement rings coupled with Diamonds. The finest sapphires can be found in parts of India (Ceylon) & Sri Lanka.


Ruby is the only variety of Sapphire to be given a unique name. Ruby is the birthstone of July & is the anniversary stone for the 40th Wedding Anniversary. Found in Sri Lanka, Burma & Thailand, Ruby is praised for its amazing deep red colour & is often given as a symbol of love due to its iconic association with passion & fire. The corundum family are a fairly hard wearing gemstone family & therefore are great in jewellery to be worn everyday or in rings. Ruby is usually cut in the Marquise (pointed oval) or Oval cut as this maximises the vibrant & deep hues of the gem.


Amethyst is the birthstone for February & is praised for its deep purple colour. It is one of the most common gemstones available & has one of the deepest histories as a gemstone to be worn in jewellery. Amethyst is a very regal gemstone & was commonly set into the decorative riches of royality from all over the world including the Crown Jewels. Amethyst takes its name from the Greeks, mythology tells of a servant girl named Amethyst who when Bacchus (God of wine) threatened to set his tigers upon in anger, was turned into a quartz statue by Goddess Diana. Bacchus was so remorseful, he poured his wine over the statue turning it purple. Amethyst possesses pietzoelectric properties (emits a small charge when electricity is passed through) hence has been used in quartz watches for centuries.


Topaz (also known as Citrine when heated to create an orange variety) can occur in most colours naturally. It is the birthstone for November & is most popular when blue. Topaz is thought to have healing powers, in medieval times a Topaz talisman was believed to guard against mental disorder. Topaz is believed to take its name from the Sanskrit word 'Tapas' meaning fire making reference to the orange varieties found. The best sources of Topaz are Russia & Brazil. Topaz has a hardness of 8 on the MOHs scale therefore should be stored away from other gemstones, as Diamond should be, to prevent the scratching of other gemstones.


Opal is the birthstone of October & is popular for its illuminscence & opalescence (ability to displays flashes of colour within the gemstone besides the main colour - eg, in white opal flashes of pink, green & red are displayed). Opal is a very soft gemstone made up of Silica (salt) & water. It must be oiled occasionally to maintain its beauty & is usually cabochen cut (smooth & polished) to allow its stunning visual properties to be displayed to best effect. Opal can occur in many colours although white & black opals are the most popular. The most stunning opals are found in Japan & Southern Australia. Opal has been popular since Roman times & is often worn in lavish rings & pendants for best effect. Opal can also be worn near the heart in necklaces as a taliman to protect travellers & was once ground up & used in spells for witch craft. Opal needs special care & cleaning in order to maintain its stunning look. It must never be cleaned using harsh chemicals or exposed to heat.


Garnet was named by the Greeks because it reminded them of Pomegranate seeds (granatum in Greek). They deep red wine colour is visually stunning & has been used since 3100BC in jewellery pieces. Garnet is extremely hard & has often been used in industry to work wood or metal. Garnet was often confused with Ruby in ancient times hence there are many gemstones such as Uralian Garnet which bear the name but are in fact not a variety of Garnet. The finest garnet is found in Kenya, Sri Lanka & Brazil.


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