pegmatite: meaning, definition, pronunciation and examples
C2Technical/Scientific
Quick answer
What does “pegmatite” mean?
A very coarse-grained igneous rock, typically granite, with exceptionally large crystals, often containing rare minerals.
Audio
Pronunciation
Definition
Meaning and Definition
A very coarse-grained igneous rock, typically granite, with exceptionally large crystals, often containing rare minerals.
In geology and mining, a rock formation sought for its large crystals and valuable mineral deposits like lithium, tantalum, and gemstones.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Pronunciation differs slightly (see IPA).
Connotations
Neutral technical term in both varieties.
Frequency
Equally rare and technical in both BrE and AmE, used only within relevant scientific/industrial fields.
Grammar
How to Use “pegmatite” in a Sentence
The [LOCATION] contains significant pegmatite deposits.Miners are extracting [MINERAL] from the pegmatite.The pegmatite intrudes into the surrounding [ROCK TYPE].Vocabulary
Collocations
Examples
Examples of “pegmatite” in a Sentence
verb
British English
- The granite body locally pegmatites near its margins.
- The magma began to pegmatite as it cooled slowly.
American English
- The pluton pegmatites in its upper section.
- The process that forms these rocks is called pegmatitization.
adverb
British English
- The rock crystallised pegmatitically, forming huge feldspars.
- The minerals are distributed pegmatitically within the dike.
American English
- The mass cooled pegmatitically, resulting in the large grain size.
- The fluids evolved pegmatitically.
adjective
British English
- The pegmatitic phase of the intrusion is highly mineralised.
- They identified a pegmatitic texture in the sample.
American English
- The pegmatitic zone yielded excellent tourmaline crystals.
- Pegmatitic fluids are rich in volatile elements.
Usage
Meaning in Context
Business
Used in mining industry reports and investment materials concerning rare earth elements or gemstones.
Academic
Common in geology, earth science, and mineralogy textbooks, research papers, and lectures.
Everyday
Virtually never used in everyday conversation outside of specific hobbies (e.g., rock collecting).
Technical
The primary context. Used in geological surveys, mining engineering, and mineral exploration.
Watch out
Common Mistakes When Using “pegmatite”
- Mispronouncing as /pegˈmætaɪt/ (stress on second syllable).
- Using it as a general term for any crystalline rock.
- Misspelling as 'pegmite' or 'pegmatight'.
FAQ
Frequently Asked Questions
Pegmatite is a variant of granite, distinguished by its extremely coarse crystal texture. All pegmatites are granitic in composition, but not all granites are pegmatites.
They are primary sources for rare elements like lithium, beryllium, tantalum, niobium, and cesium, as well as for industrial minerals like feldspar, mica, and quartz, and for gemstones like tourmaline and topaz.
No, pegmatites typically form from the last, water-rich residues of granitic magmas. This high water content allows ions to move freely, enabling the growth of very large crystals.
No, it is a highly specialized term used almost exclusively in geology, mineralogy, and the mining industry. It is unlikely to be encountered in everyday language.
A very coarse-grained igneous rock, typically granite, with exceptionally large crystals, often containing rare minerals.
Pegmatite is usually technical/scientific in register.
Pegmatite: in British English it is pronounced /ˈpɛɡmətaɪt/, and in American English it is pronounced /ˈpɛɡməˌtaɪt/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “None. It is a technical term with no idiomatic usage.”
Learning
Memory Aids
Mnemonic
Think of a PEG holding a MIGHTY (matite) giant crystal. PEG-MIGHTY = PEGMATITE, a rock with mighty big crystals.
Conceptual Metaphor
A PEGMATITE is a MINERAL SUPERMARKET (because it contains a large, diverse concentration of rare minerals in one place).
Practice
Quiz
What is the most defining characteristic of a pegmatite?