Wairakite is a

zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These pos ...

mineral with an analcime structure but containing a

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

ion. The chemical composition is Ca₈(Al₁₆Si₃₂O₉₆)•16H₂O. It is named for the location of its discovery in

Wairakei Wairakei is a small settlement, and geothermal area a few kilometres north of Taupō, in the centre of the North Island of New Zealand, on the Waikato River. It is part of the Taupō Volcanic Zone and features several natural geysers, hot pool ...

, North Island, New Zealand, by Alfred Steiner in 1955. The first finds were in hydrothermally altered

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

s, ignimbrites and

volcaniclastic rock Volcaniclastics are geologic materials composed of broken fragments (clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it ...

s. The mineral has since been found in

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...

s and in geothermal areas. It was most likely first successfully synthesized in a laboratory in 1970.

References

Zeolites Monoclinic minerals Minerals in space group 15 {{silicate-mineral-stub