Mineral Definition and Identification

Overview

This lecture explains the five-part scientific definition of a mineral, highlighting common examples and clarifying key concepts for identification.

Minerals are found in many everyday products (e.g., calcite in toothpaste/cement, gypsum in sheetrock, bentonite clay in ice cream).
Minerals can be both useful and collectible for their beauty.

A mineral must be naturally occurring (formed without human intervention).
A mineral is always a solid (not a liquid or gas).
Minerals are inorganic, meaning they are not derived from living organisms.
Each mineral has a definite chemical formula (fixed atomic composition).
Minerals display a crystalline structure (atoms arranged in a specific, repeating pattern).

Calcite (calcium carbonate), pyrite (iron and sulfur), and olivine (magnesium, iron, silicon, oxygen) are minerals with specific formulas.
Diamonds from the earth are minerals; lab-made diamonds are not.
Coal is not a mineral because it's derived from plant material (organic).
Water (H₂O) has a chemical formula but is not a mineral unless solid (ice).
Crystalline structure determines physical properties; graphite and diamond are both pure carbon but differ in structure and hardness.

Objects to consider if they're minerals: kitchen glass, oil, volcanic glass (obsidian), quartz, wood, frozen water (ice).
Classification depends on applying the five-part definition.

Mineral — A naturally occurring, inorganic solid with a definite chemical formula and crystalline structure.
Inorganic — Not derived from living organisms.
Crystalline Structure — Atoms arranged in a specific, repeating pattern.
Polymorphs — Minerals with the same chemical composition but different crystalline structures (e.g., diamond and graphite).

Review the definition of a mineral and practice applying it to different substances.
Check provided practice answers to test your understanding.