Zeolites are a form of naturally occurring volcanic rock composed of hydrated aluminosilicates of the alkali earth metals. Naturally occurring zeolites are rarely pure and are contaminated to varying degrees by other minerals, metals, quartz, or other zeolites. This is why naturally occurring zeolites are excluded from important commercial applications where uniformity and purity are essential. For commercial use, synthetic zeolites are used. Produced into a uniform, phase-pure state, synthetic zeolites and hold some key advantages over their natural form, namely being in a uniform, phase-pure state. Zeolites have a high affinity for water and are capable of adsorbing and de-sorbing it without damaging its crystal structure. This property makes them very efficient at removing excess moisture from the air.