16th Wedding Anniversary Gift
Peridot – a green variety of the Olivine mineral which is found in lava and meteorites.
Unlike many other gemstones, peridot occurs in only one colour (although the shade does vary). The unique green of the peridot is caused by the iron in its chemical composition and the fact that its colour is part of its intrinsic chemical composition, (it would not exist without the iron) means that it is termed idiochromatic (self coloured) whereas gems that occur in a variety of colours (e.g. sapphire) are coloured by impurities in their composition and they are termed allochromatic (meaning “added colour”) as in their pure form they are colourless.
Another feature of peridot that sets it apart from many other gems is that it is not enhanced or heat treated to alter its colour. However, sometimes, if the gem contains surface reaching fissures, there can be treatment of colourless oil, wax or resin to improve the clarity of the stone, This type of treatment MUST be disclosed to the purchaser.
In addition to being honest to the purchaser about treatments, it is important information that a should be passed on to a workshop if any work is ever needed on an item containing a gem treated in this way as incorrect heating or cleaning of the item could result in the oils, wax or fillers being stripped from the stone leaving a very different looking material afterwards.
Peridot is a gemstone that was referred to in the Bible (under its original name of Chrysolite) and it has been mined for over 4000 years. The Egyptians often made peridot beads. Rings and pendants have been found dating back to Roman times.
Peridot is one of the gemstones that was used in the manufacture of Suffragette jewellery. We will have a more detailed post about this in the future. The suffragette movement used the colours green, white and violet to represent in that same order, hope, purity and Royalty. The gemstones used tended to be peridot for hope, pearls for purity and amethyst for violet. The three colours with the initial letters G W V was used in Britain as a code for Give Women Votes.
Peridot is not as durable as some gemstones and will scratch more easily so it tends to be more suited to earrings and pendants but, as long as care is taken to prevent abrasion and loss of polish, it can be worn in rings but it is a stone that really should be removed from the hand if any hard manual work is done.
The main localities in which peridot is found today are the USA, Myanmar (Burma), Pakistan and the Himalayas.
Due to the size that some peridot crystals can grow to, it is not unusual for designers to created a piece to fit the stone rather than trying to put the peridot into a pre-made setting.
Peridot exhibits a phenomenon called PLEOCHROISM which is when a gem marerial shows two (dichroic) or three (trichroic) different colours as you turn the stone. In peridot, the dichroism is quite subtle, showing a weak yellow-green in one direction and green in the other. Gemmologists use an instrument called a dichroscope to allow this feature to be seen. It is an effect that can help with the identification of many gems.
Another feature seen in some peridot gemstones is an inclusion (an item, often of crystalline matter, that was present when the gemstone formed) in the shape of a ‘lily pad’. You can see this clearly in the photograph below and you can also see double facet edges at some points and this is due to the amount of double refraction possessed by peridot. (the degree to which the light ray splits into two rays when it passes through the gem from the air).
Care of your peridot jewellery:
When cleaning your peridot jewellery, you should NEVER put the items into an ultrasonic cleaner or subject them to steam cleaning as this can damage the stones. Soaking in some warm soapy water and using a soft brush to clean around the setting should be perfectly adequate to clean the item. The very small ‘interdental’ toothbrushes can be very useful to clean in between the settings. DO NOT soak jewellery containing pearls or any porous material like opals or turquoise as it could affect the settings and the look of the stone.
