Gemology is the study of natural and synthetic precious and semi-precious gems found in nature. Gemologists are professionals who inspect, identify, grade and measure gemstones for their ownership, use, or trading. Examining a gemstone, which can be either a wild mineral or a man-made laboratory formed gem, is the most important stage of the gemology process. The gem is inspected under specialized equipment such as light microscopes, polarizing microscopes, ultraviolet light sources and spectrometers.

Gemologists use the 4Cs of diamond grading: i.e. Color, Cut, Clarity and Carat Weight as standards to grade natural gems. The 4Cs must be considered together as a whole to determine the beauty and value of a gemstone. The grading done by gemologists is numerous and complicated, relying on years of knowledge, experience, and training to assess the precise condition and first-rate quality of the gemstone. Lab-grown gems, natural gems, and imitation gems all require different examination criteria and must be subjected to extensive study to determine authenticity.

Gemology is traditionally divided into two subcategories: precious stones (the five traditional precious stones are diamond, ruby, sapphire, emerald, and opal) and semi-precious stones (stones below the quality of a precious stones). This is not only a qualitative judgement however, as some stones, such as jade, may be more valuable than some more popularly known precious stones. Furthermore, some stones are more valuable when they number four instead of three.

Precious stones and semi-precious stones as well as gemstones come in a variety of locations, cuts and shapes and become a popular investment for many reasons. For one, gems have historical, financial, and aesthetic significance. Alternately, investing in precious metals and gemstones is less speculative for inexperienced investors, it is a simpler process, and it offers the potential for both short-term and long-term gains. It is important to remember however, that investing in gemstones may be risky, as these investments may not be as easily liquidated if you suddenly need cash.

Overall, gems and gemology are a complex and fascinating subject, requiring a lifetime of learning, practice, and commitment. Professionals in this field must be extremely knowledgeable about both the technical and aesthetic characteristics of gemstones, which is why the undertaking of such a task must be performed by those with a deep understanding and experience with the examination, grading, and trading of gemstones on the whole.