Why do crystals grow in different temperature?

Some minerals will not form with just temperature alone, like diamonds, need immense pressure as well as temperature to form. Other minerals are formed from hydrothermal fluids that come to the surface along fault lines or in geothermally active areas. Some minerals can even be grown in a laboratory, I have a few lab grown crystals that have the most amazing structure.
Most crystals are found in protected areas, like caves, because they take a long time to form and if the environment or conditions change then growth will stop.