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Atoms in formation

What Is a Mineral?

A mineral is a natural solid whose atoms are stacked in a strict repeating pattern.

A crystal you canhold Atoms stacked in arepeating pattern
The outside shape comes from the inside order.

  1. Step 1 of 5

    A mineral has a fixed recipe.

    A mineral Fixed formula, everytimeA rock A mixture of severalminerals

    Salt is always sodium and chlorine in equal numbers. Quartz is always one silicon to two oxygens. The formula does not vary.

  2. Step 2 of 5

    Its atoms repeat in a strict pattern.

    Glass Atoms jumbled — not amineralQuartz Atoms in a repeatinglattice

    The atoms sit in a lattice that continues identically in all directions. That internal order is what separates a mineral from ordinary solid matter.

  3. Step 3 of 5

    The pattern shows up on the outside.

    1 Cubic atomicstacking2 Grows outwardthe same way3Cubic crystalsyou can see

    Flat faces and sharp angles are the lattice made visible. Salt makes cubes because its atoms stack in cubes — it cannot make anything else.

  4. Step 4 of 5

    It also decides how a mineral breaks.

    Weak planes Splits into flat sheetsNo weak planes Breaks unevenly

    Some lattices have weak planes, so the mineral splits into perfect sheets. Mica peels into transparent flakes for exactly this reason.

  5. Step 5 of 5

    Rocks are mixtures of minerals.

    A piece of granite Grains of threedifferent minerals

    Granite is quartz, feldspar and mica together — you can see the separate grains. The minerals are the ingredients; the rock is the dish.

    Around 6,000 minerals are known, but about a dozen make up nearly all the rock on Earth.

The short version

A mineral is a natural solid with a fixed formula and a repeating atomic lattice — and the lattice shapes the crystal.

Try it yourself

Look at a granite worktop closely. The pink, white and black speckles are three different minerals in one rock.

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