What is a Mineral?

A Scientific Definition of a Mineral

Scientific definitions for minerals vary somewhat, but the following scientifically accepted definition is short and easy to remember.

A mineral is a naturally occurring solid substance with a definite chemical composition and a specific crystal structure.

Let’s take a closer look at each condition.

Naturally Occurring

Minerals must form through natural processes. Consequently, synthetic or lab-created materials, like lab-created corundum (ruby and sapphire), are not minerals. Although gemologists can say lab-created rubies and sapphires are real rubies and sapphires, as well as real gemstones, it would be incorrect to call them minerals. In the United States, synthetic materials with the same properties as minerals can’t be called minerals in advertisements. Mineralogists refer to these products simply as synthetic materials, even if they are physically and optically identical to minerals.