Peridot is the birthstone of August. It’s also in the olivine isomorphic gemstone family. What do I mean by this? Well… its chemical composition is (Mg,Fe)₂SiO₄. The ratio of Magnesium to Iron changes the stone’s name from a Peridot to a Forsterite. Leaving behind the nuances of peridot, it is essentially a gemstone in abundance. However, getting jewellery quality peridot, without any inclusions, is relatively difficult. That being said in The Gem Monarchy’s collection of gemstones, we do have jewellery quality peridot.

For today’s inclusion, we took a peridot that was recently in our rejected jewellery quality stock of gemstones. The stone itself was full of these “black spots” which to the microscope aren’t just that. In observing today’s gemstone, it was interesting to use a couple of different photography tools(the DSLR Camera, as well as the iPhone). We will have a look at the resulting images from both.

The image below is the DSLR image of the “black dot” inclusion within the peridot. When we put it under the microscope the black dot becomes a crystal inclusion. We suspect the crystal itself to be either biotite or garnet, especially looking at the reddish-brown colour of the inclusion. To tell them apart we’d need more specific laboratory equipment. This inference is in sorts with the out-of-focus secondary inclusion on the right-hand side of the image. Surrounding the main inclusion is the lilypad itself, which is a rounded fracture where the crystal is the perpetrator.

Iridescence of the Lilypad

Because the lilypad is by definition a fracture, there is a very large likelihood that light behaves uniquely in and around the lilypad. Firstly, we are able to see the hint of iridescence seen in the lilypad itself at the 5 o’clock position. And secondly, we are able to see the iridescence much better in the iPhone photo, which is below. The mixture of yellow and blue to purple is the light bending and reflecting in the lilypad is absolutely gorgeous. We know the cause to be the difference in medium causing light to split to the different colours of the rainbow. This presence of lilypads makes the peridot a unique gemstone.

Conclusion

Conclusively this stunning inclusion is an absolute delight to look at. The concept: a crystal inclusion causing a fracture that bends light to make a rainbow, is the running theme within peridot. The exact crystal type which caused this inclusion is still inconclusive and needs further microscopic adjunct testing. But what we were able to conclusively agree is that this has caused a liypad.

The beauty of the world of inclusions acting on the light makes for an extravagant image allowing an appreciation of what we can’t see to the naked eye.

Hope everyone enjoyed this rendition of what a lilypad inclusion was through the lens of a microscope.

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