iddingsite
Sign in to saveIddingsite is a microcrystalline rock that is derived from alteration of olivine. It is usually studied as a mineral, and consists of a mixture of remnant olivine, clay minerals, iron oxides, and ferrihydrites. Debates over iddingsite's non-definite crystal structure caused it to be de-listed as an official mineral by the IMA; thus, it is properly referred to as a rock.
Wikidata facts
- Instance of
- mixture
- Named after
- Joseph P. Iddings
- Image
- Idyngsyt BA.jpg
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Encyclopedic overview
8 sectionsContents
- Introduction
- Composition
- Geologic occurrence
- Structure
- Physical properties
- References
- Additional sources
- External links
Iddingsite is a microcrystalline rock that is derived from alteration of olivine. It is usually studied as a mineral, and consists of a mixture of remnant olivine, clay minerals, iron oxides, and ferrihydrites. Debates over iddingsite's non-definite crystal structure caused it to be de-listed as an official mineral by the IMA; thus, it is properly referred to as a rock.
Iddingsite forms from the weathering of basalt in the presence of liquid water and can be described as a phenocryst, i.e. it has macroscopically visible crystals in a fine-grained groundmass of a porphyritic rock. It is a pseudomorph that has a composition that is constantly transforming from the original olivine, passing through many stages of structural and chemical change to create a fully altered iddingsite.
Excerpted from Wikipedia’s “iddingsite” article, available under the CC BY-SA 4.0 licence.