Variables that control crystal growth include the amount of dissolved material, evaporation, pressure and temperature. The higher the amount of dissolved material in the water and the more pressure that is placed on the material, the bigger the crystals will grow.

What determines the size of crystals?

The size of the crystals depends on how quickly the molten magma solidified: magma that cools slowly will form an igneous rock with large crystals. lava that cools quickly will form an igneous rock with small crystals.

How do you increase the size of crystals?

Size Matters Crystals that grow more slowly, tend to be larger. For crystals that were grown by slow cooling of the solvent: it usually improves the quality and size of the crystals, if the solution is slowly warmed up until alomst all crystals are dissolved again and than cooled dwon a second time very slowly.