Zeolite:
A group of hydrous aluminosilicates that are similar to the feldspars. They easily lose and regain their water of hydration and they fuse and swell when heated. Zeolites are frequently used in water softening, ion exchange and absorbent applications.
Zinc Blende:
A term used in reference to the mineral sphalerite.
Zirconium:
A mineral, zirconium silicate. A hard mineral with a high index of refraction that is used as a gemstone and as an ore of zirconium.
Zoned Crystal:
A crystal that grew while temperatures were changing or while the composition of the parent solution was changing. Crystals of these minerals can have a range of compositions, with a certain chemistry in the center reflecting the early growth conditions and the outer chemistry reflecting the later growth conditions. Minerals such as olivine or plagioclase which have a solid solution series frequently form such crystals.
Zone of Aeration:
A zone between the land surface and the water table where pore spaces are filled mainly with air. Water that exists in the pore space in this zone is referred to as "soil moisture".
Zone of Saturation:
The zone beneath the water table where all pore spaces are completely filled with water. Water that exists within this zone is known as "ground water".
Zone of Weathering:
A subsurface area, above the water table, where mineral and organic materials are subject to weathering.