Which is NOT one of the criteria for defining a mineral?

• A. Organic origin
• B. Naturally occurring
• C. Solid
• D. Definite chemical composition

Answer: (A)

Minerals are defined by being natural, inorganic solids with a definite chemical composition and a crystal structure. Organic origin doesn’t fit this definition because minerals are not based on life processes or organic compounds; they form from inorganic chemical combinations in geological environments. The other criteria—naturally occurring, solid, and having a definite chemical composition (plus a crystalline arrangement)—are the essential traits minerals share. Some minerals can show slight compositional variation, but they still have a defined chemical formula and orderly internal structure. So organic origin isn’t a defining criterion.