gabbro
LowTechnical / Scientific (Geology)
Definition
Meaning
A dark, coarse-grained igneous rock, chemically equivalent to basalt but formed by slow cooling deep underground.
Any of a group of dark, plutonic rocks composed chiefly of pyroxene and calcium-rich plagioclase feldspar.
Linguistics
Semantic Notes
The term is specific to geology and petrology. While it has a precise scientific definition, in broader contexts it may be used loosely to describe any dark, heavy, coarse-grained rock.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage between British and American English within the geological community.
Connotations
The term is purely denotative in both varieties, carrying no additional cultural or social connotations.
Frequency
Equally low frequency and restricted to technical geological contexts in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
[The/This] + gabbro + [verb e.g., contains, forms, intrudes]gabbro + [of + location e.g., of the Scottish Highlands][Adj. e.g., layered, massive] + gabbroVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Usage
Context Usage
Business
Virtually never used.
Academic
Used in geology, earth sciences, and archaeology. Found in research papers, textbooks, and field reports.
Everyday
Extremely rare. Might appear in travel guides to areas with notable geology (e.g., Isle of Skye).
Technical
The primary context. Used for precise rock classification in geology, mining, and construction (as dimension stone).
Examples
By Part of Speech
adjective
British English
- The gabbroic intrusion was mapped over several kilometres.
- Gabbro pegmatites are found at the margins.
American English
- The gabbroic intrusion was mapped over several kilometers.
- Gabbro pegmatites are found at the margins.
Examples
By CEFR Level
- The mountains contain a rock called gabbro.
- Gabbro is dark and heavy.
- Geologists identified the intrusion as a coarse-grained gabbro.
- Gabbro is often quarried for use as a decorative building stone.
- The gabbro pluton exhibits cumulate textures, indicative of fractional crystallisation within a magma chamber.
- Economic nickel-copper sulphide deposits are frequently associated with noritic varieties of gabbro.
Learning
Memory Aids
Mnemonic
Imagine a GABBling geologist BROwning over a dark, coarse rock. GABB + BRO = GABBRO.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'габбро' – it is a direct loanword with identical meaning. No trap.
Common Mistakes
- Pronouncing it with a hard 'g' as in 'go' (it's /ɡ/ as in 'get').
- Misspelling as 'gabro'.
- Confusing it with 'basalt' (its fine-grained extrusive equivalent).
Practice
Quiz
Gabbro is most closely related to which of the following rocks?
FAQ
Frequently Asked Questions
Gabbro and basalt have the same chemical composition but different textures. Gabbro is coarse-grained due to slow cooling deep underground (intrusive), while basalt is fine-grained due to rapid cooling on the surface (extrusive).
Yes, in specific contexts. Certain types are quarried as dimension stone for countertops, tiles, and facing stone (often sold as 'black granite'). It can also host valuable ore deposits.
Almost never. As an igneous rock formed from molten magma at high temperatures, any pre-existing fossils would be destroyed during its formation.
It originates from the Italian name for a Tuscan hamlet, 'Gabbro', where the rock was originally described by geologists in the 18th century.