How Do Crystals Grow?

Step 1 of 5

A liquid can only hold so much.

Dissolved substance stays put while there is room. Once the liquid is saturated, anything extra must come out as solid.

Step 2 of 5

Atoms attach in a specific arrangement.

Each atom fits onto the growing solid in only certain positions, determined by its shape and charge. That pattern repeats indefinitely.

Step 3 of 5

That is why crystals have flat faces.

A repeating internal pattern produces flat outer surfaces at fixed angles. Salt makes cubes because its atoms stack in cubes.

Step 4 of 5

Slow growth makes bigger crystals.

Rapid cooling starts millions of tiny crystals at once. Slow cooling lets a few grow large, which is why patient methods give better results.

Step 5 of 5

It happens in nature the same way.

Mineral-rich water slowly evaporating or cooling in rock cavities grows crystals over thousands of years — sometimes metres long.

A cave in Mexico holds gypsum crystals over ten metres long, grown in warm mineral water over half a million years.