Which statement best defines an inclusion?

• A. A surface blemish
• B. A color zone
• C. A clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface
• D. A natural pearl

Answer: (C)

An inclusion is a feature that lies inside a gemstone, originating during growth or later formation, and it can be completely enclosed or it can reach into the interior from the surface. This definition matters because it distinguishes internal characteristics from surface flaws. The best description is the one that states an inclusion is a clarity feature totally enclosed in a polished gemstone or extending into it from the surface, since it covers both internal inclusions and those that originate at the surface. The other options describe surface blemishes, color zones, or an unrelated gem type, which do not fit the concept of an inclusion.