dunite
Very LowSpecialized Technical
Definition
Meaning
A type of ultramafic and plutonic rock, consisting almost entirely of the mineral olivine (typically forsterite).
A rock type significant in geology and petrology, often associated with the Earth's mantle and as a host rock for certain mineral deposits like chromite. The name originates from Dun Mountain in New Zealand.
Linguistics
Semantic Notes
This is a hypernym for a specific rock type. It belongs to the broader category of 'peridotites'. The term is primarily taxonomic within geological classification systems.
Dialectal Variation
British vs American Usage
Differences
No lexical differences. Pronunciation and spelling are identical.
Connotations
None beyond the technical definition.
Frequency
Equally rare and technical in both varieties; used exclusively in geological and mining contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
The [geological feature] is composed of dunite.[Chromite] is often found within dunite.The dunite [shows/exhibits] a granular texture.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Rarely used; might appear in reports for mining or mineral exploration companies focusing on chromite or platinum-group elements.
Academic
Primary context. Used in geology, petrology, and earth science papers, textbooks, and lectures to describe a specific rock type.
Everyday
Virtually never used in everyday conversation.
Technical
Standard term in geological surveys, petrographic descriptions, and resource assessments.
Examples
By Part of Speech
adjective
British English
- The dunitic sample was collected for analysis.
- Dunitic layers are interbedded with the harzburgite.
American English
- The dunitic composition indicates a mantle origin.
- They identified a dunitic pod within the larger formation.
Examples
By CEFR Level
- This rock is called dunite. It is very green.
- Dunite is a green rock made mostly of olivine.
- Geologists study dunite because it is thought to be a major component of the Earth's upper mantle.
- The podiform chromitite deposits are typically hosted within a dunite matrix, suggesting a complex magmatic segregation process.
Learning
Memory Aids
Mnemonic
DUNite is Dense, Ultra-mafic, and Named after Dun Mountain. Or: Think of a DUNE made not of sand, but of dense green olivine.
Conceptual Metaphor
A piece of the Earth's mantle brought to the surface (a 'mantle sample').
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'дунит' (which is the direct translation). It is a precise scientific term with no common alternative.
Common Mistakes
- Misspelling as 'dunight' or 'dunaite'.
- Using it as a general term for any dark rock.
- Incorrect pronunciation stressing the second syllable (/djuːˈnaɪt/).
Practice
Quiz
Dunite is primarily composed of which mineral?
FAQ
Frequently Asked Questions
No, it is relatively rare at the Earth's surface but is a significant rock type in the upper mantle.
It is typically various shades of green, grey-green, or brownish-green due to its high olivine content.
It is found in ophiolite complexes (slices of oceanic crust pushed onto continents), in layered igneous intrusions, and as xenoliths in volcanic rocks.
It is not a major commercial rock. Its main economic significance is as a host for chromite deposits. It is sometimes used as a dimension stone or for refractory purposes.