It tell's the story of a gem’s creation.
Small foreign bodies and minerals that are trapped inside a gemstone as it forms are known as ‘inclusions’ or, more poetically, “Mother Nature’s fingerprints”. As most gems are created under immense amounts of pressure and extreme stress and heat, the more inclusions you see, the more incredible colossal natural events the gem has likely witnessed!
Are inclusions flaws? Are they good or bad? Are you seeing a blemish when someone would see a beauty spot? Do they affect the value? Yes, no, sometimes, maybe! Sometimes they add value, sometimes they render a gem almost valueless.
Although inclusions are normally regarded as a negative, in stones such as Rutilated Quartz and Amber, their presence adds to the beauty of the gem and is therefore seen as a benefit. Also, as most synthetic and fake gems do not have inclusions, when they are seen in gemstones, at least you know the likelihood is that you are looking at a genuine article from Mother Nature.
Some gems (such as Bixbite, Rubellite and Emerald) are more naturally ‘included’, whereas Aquamarine, Topaz and Amethyst are normally relatively inclusion free.
Inclusions in some gemstones are actually precious metals such as pure gold; in Diamonds they are sometimes small pieces of Peridot locked within the gem.
Many people use the words ‘flaws’ and ‘inclusions’ to mean the same thing, when in reality they should be treated separately. To me a flaw is something inside a gemstone or on its surface that unquestionably, without any doubt, detracts from its value. A chip on the girdle of a gem, a crack on its crown, huge inclusions that spoil the look of the gem: these are all flaws. An inclusion on the other hand, especially if it is small, is a story teller. It’s telling you in pictures about the strains and the stresses it endured during its millions of years in the making. It’s saying ‘look at me, I am genuine, I was not grown in a laboratory’. The inclusions may even be a different crystal altogether, which grew inside the gem during its genesis. This is in fact the meaning of the term ‘inclusion’.
Many people believe that you should study gemstones under microscopes to judge their clarity and even the GIA (Gemological Institute of America) support this by saying you should judge a Diamond’s clarity by using a 10x magnification loupe. But if you grasp the other measurements for forming an opinion of a gemstone, such as understanding its brilliance/life, its tone and saturation, being able to tell if the gem is well cut or has an oversized window or is cut too shallow, then you really should not measure its clarity with magnification, but with your naked eye.
So are inclusions good or bad? Well, that depends very much on the gemstone species and variety. If it is a Star Sapphire or Star Ruby, then without a mass of inclusions you will not see the star effect. If the gem is a Cats Eye Chrysoberyl, no inclusions means no chatoyancy. If it’s a Cashmere Sapphire (considered by most in the trade as the finest Sapphire on the planet), then without inclusions you won’t witness its trademark sleepy glow. No inclusions in Rutile Quartz means it is not Rutile Quartz, but just a plain Quartz; no inclusions in Moonstone and you won’t see it glow like the moon. These are just a few examples where inclusions are welcomed, in fact highly desired, in gems.
That said, a big inclusion visible to the naked eye in a three carat Tanzanite will devalue the gemstone compared to one that appears flawless to the eye and a Sky Blue Topaz with a large inclusion will hit you like a tonne of bricks. Don’t be fooled by the salesman who says, “The inclusions in this Emerald are very normal, in fact we call it the Jardin of the gemstone (French for garden) and it increases its value”. Whilst it is true that you will nearly always see inclusions in Emeralds, a flawless piece that has great brilliance, a lovely tone and a vividness of colour, is worth far more than an equivalent gem that has a lot of visible inclusions.
