Clarity is one of the 4 famous “C”s when purchasing gemstones. In order to understand “Clarity” lets' dissect the process of crystallization.
Millions of years ago as the particular gemstone started to form there were variable surrounding conditions for crystallization. Not all of them were ideal, causing imperfections in chemical bonding, as well as other impurities to be trapped. This natural phenomenon is the cause for variation in the gemstones of the same species.
Under ideal conditions to produce a “perfect” gemstone there are several factors to consider. Not only does the chemical composition have to be ideal and constant, but the temperature and more importantly the pressure, has to be ideal to produce the preferred gemstone.
These factors are successfully reproduced in the laboratory, producing “lab created” gemstones. This ideal and controlled environment produces the “perfect” gemstones in colour and clarity.
Here is a fair word of warning: If a gemstone is perfect in every way be very careful that it is not lab created. These types of stones, if they were natural, are extremely rare and most definitely very pricy!
There are number of imperfections that can occur. Most gems contain tiny natural features called inclusions. Mostly microscopic in nature, they are easily noticed under magnification such as the loupe (10X loupe magnification is the standard for clarity classification) or more powerful microscopes.
In transparent gems, the degree of transparency and light return (brilliance) is considered crucial. Certain gemstones have the “accepted” variance and degrees of clarity not usually accepted for other gems. For example, Amethyst is generally expected to be clean and Emerald is expected to be hazy. Flawless, clean Emeralds are very rare.
The clarity of gems is determined by judging the amount and location of inclusions seen. Basically, the higher the clarity grade, the higher the value of the gem. In general, inclusions that don’t interfere with the brilliance, sparkle and fire of a gem don’t affect the value.
Here is some terminology used in classifications of gems according to their Clarity:
Fl – flawless, very rare with no natural inclusions visible under 10X magnification.
VVS1 – Very, very small inclusions visible under 10X magnification.
VVS2 – Slightly more than VVS1, however still very, very small inclusions.
VS1 – Gemstones with larger inclusions, however still very small under 10X magnification.
VS2 – Larger inclusions than VS1, but still small, are classified.
SI1 & SI2 - Gems that have some inclusions visible to the naked eye but not to the extent of affecting the brilliance of the gem.
I1 & I2 I1 - These gems have some larger and/or many minor inclusions that somewhat diminish the brilliance of the gem.
