in·clu·sion | in-ˈklü-zhən
noun
A visible internal flaws in a gemstone, including: fractures, crystalling abnormalities, and foreign objects
An inclusion in a diamond refers to the small imperfections that form within a diamond naturally. These can include foreign objects, abnormalities in the crystallization of the diamond, fractures, or mineral deposits that formed over time within the gem. Inclusions are normal for all diamonds, which flawless diamonds being incredibly rare - most named and some gemologists having never seen a naturally flawless stone. That does not mean, however, that inclusions are easy to see. High-graded diamonds may still have inclusions, but they are only seen at 10x magnification. These may include pinpoint inclusions, feather inclusions, or diamond cavities.
