Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat Articles
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Ruatapu Cave (Alum Cave), Orakeikorako Thermal Area (Orakei Korako; The Hidden Valley), Taupo District, Waikato Region, North Island, New Zealand

This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84): 38° 28' 32'' South , 176° 9' 3'' East
Latitude & Longitude (decimal): -38.47556,176.15111
Köppen climate type:Cfb : Temperate oceanic climate

Ruatapu or "Alum" Cave is one of the few caves known to have developed within an active thermal field. The Orakei Korako thermal area is dominated by alkali-chloride alteration but the cave hosts a steaming acid-sulphate pool and a series of efflorescences and other minerals produced as a result of acid-sulphate alteration of the host rocks (tuff).

While some caves in Australiasia produces powdery minerals from the interaction of bat guano and the chemistry in the wall rocks, at Ruatapu Cave new minerals are formed from the interaction of steam condensate, heat, and the wall rock chemistry. Kaolinite, opal-A, cristobalite, alunite, alunogen dominate the assemblage near the cave mouth. As conditions change further into the cave, tamarugite and potash alum form efflorescences, with lesser alunogen, meta-alunogen, mirabilite, halotrichite, kalinite, gypsum and tschermigite. Jarosite crusts have developed where acid sulphate pools meet ignimbrite wall rock covered in once living microbial mats. Decreases in water levels causes the jarosite to alter to potash alum, akaganeite, and schwertmannite.

Sometimes marketed as Aladdins Cave.

Mineral List

19 valid minerals.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

0 - 2.588 Ma

ID: 3187411
Cenozoic volcanic rocks

Age: Pleistocene (0 - 2.588 Ma)

Lithology: Ignimbrite(s); felsic volcanic rocks; rhyolite

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

0.0117 - 2.588 Ma

ID: 1310439
Middle Quaternary lake deposits

Age: Pleistocene (0.0117 - 2.588 Ma)

Stratigraphic Name: Pakihi Supergroup

Description: Laminated, commonly diatomaceous, pumiceous silt, locally including water-lain pyroclastics.

Comments: Zealandia Megasequence Terrestrial and Shallow Marine Sedimentary Rocks (Neogene)

Lithology: Silt, pyroclastic material

Reference: Edbrooke, S.W., Heron, D.W., Forsyth, P.J., Jongens, R. (compilers). Geology Map of New Zealand 1:1 000 000. GNS Science Geological Map 2. [12]

Middle Pleistocene
0.126 - 0.781 Ma

ID: 1319877
Middle Pleistocene lake deposits

Age: Pleistocene (0.126 - 0.781 Ma)

Description: Silty, commonly diatomaceous, millimetre-laminated lacustrine sediments; dominated by pumice, lava fragments and felsic crystals.

Comments: Middle Pleistocene lake deposits. Age based on mixed

Lithology: Major:: {silt},Minor:: {sand, clay, pumice}

Reference: Heron, D.W. . Geology Map of New Zealand 1:250 000. GNS Science Geological Map 1. [13]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Rod Martin, Minerals of Ruatapu Cave, Orakei Korako, Taupo Volcanic Zone. Essence of Microscope (NZ).
Cody, A. D., (1978) Ruatapu Cave, Orakei Korako. New Zealand Speleological Bulletin. 6, 184-187.
Rodgers, KA, Hamlin, KA, Browne, P.R.L., Campbell, K.A. and Martin, R. (2000) The steam condensate mineralogy of Ruatapu Cave, Orakei Korako geothermal field, Taupo Volcanic Zone, New Zealand. Mineralogical Magazine. 64(1), 125-142.

External Links

Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2019, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: May 26, 2019 06:06:29 Page generated: March 24, 2018 22:18:47
Go to top of page