Peridot is a lime-green variety of the mineral olivine and is one of the sole gemstones found in one colour. Peridot is one of the world’s oldest known gemstones and is believed to have first formed early on during the Earth’s creation. As magma gradually cooled, some parts slower than others, it solidified as igneous rock. Due to this difference in time and temperature, larger, clearer bits of rock were created, and thus peridot was born.
Peridot is known for its signature lime green colour, and unlike most gemstones, it is only available in one main colour: green. This makes it an idiochromatic gemstone, ruby is another example of this. Gemstones that occur in a variety of colours are known as allochromatic.
Peridot is the birthstone for the month of August, as well as the gemstone given to celebrate the 16th year of marriage.
Peridot is most commonly found lining mountains in Myanmar and Pakistan; however, olivine crystals are also intermittently found in pallasites (stony-iron meteorites which have fallen to earth). These rich green meteorite crystals can then be cut into beautifully bright pieces of peridot. Peridot measures a 6.5-7 on the Mohs scale of hardness, it is a rather tough gemstone but should be worn with care, cleaned and checked regularly as to maintain its quality and value.
The green of peridot can vary depending on whether it contains hints of other colours but is ultimately a limited range from pure green, to yellowish green to greenish yellow. The brighter and more saturated the green, the higher the gemstones value. The more yellow, or even brown, tinted the peridot is, the less pure. Within this range, a peridot’s colours can appear bright green, lime green, deep chartreuse, golden green, or olive green.
The levels of iron present in a peridot affect the purity of its green hue. The less iron, the deeper the green. Peridot do not frequently get heat treated in labs in order to alternate their colour unlike many other gemstones, meaning the richness and saturation of peridot is natural and organic.