Minerals vs. Rocks

Introduction

The building blocks

People often use "rock" and "mineral" interchangeably — but to a geologist they're very different things.

A mineral is a single, pure substance with a specific chemical formula and crystal structure. A rock is a mixture of one or more minerals stuck together.

Granite, for example, is a rock — you can see the individual pink (feldspar), white (quartz), and black (mica) mineral grains if you look closely. Each of those grains is a distinct mineral with its own chemistry and crystal form.

There are over 5,500 known minerals, but just a handful — quartz, feldspar, mica, calcite, olivine, pyroxene — make up the vast majority of Earth's crust.

Key Terms — tap to expand