Ophitic
A mafic igneous texture where relatively large clinopyroxene crystals enclose smaller plagioclase laths, commonly at different orientations.
Language and route: English adjective from ophite, a name descended from Greek via Latin. English adjective from ophite, a name descended from Greek via Latin
Literal gloss: serpentine-stone-like; historically mottled
The name and its history
Historical ophite and 19th-century thin-section interpretation; first adjectival use unverified · Historical ophite and 19th-century thin-section interpretation; first adjectival use unverified
- What does the word literally mean?
- Immediate route: English adjective from ophite, a name descended from Greek via Latin. Linguistic gloss: ‘serpentine-stone-like; historically mottled’. This gloss describes language, not a demonstrated early geological theory.
- What did the original author mean?
- Ophite and ophitic inherited an older snake-skin visual analogy; nineteenth-century microscopists specified the actual feldspar-in-pyroxene relationship in dolerites.
- Why was the name needed?
- Petrographic sections disclosed a recurring contact geometry requiring distinction from simply adjacent pyroxene and plagioclase grains.
- What evidence supported the original concept?
- Plagioclase laths fully enclosed by optically continuous clinopyroxene; some early authors disagreed over breadth of the term.
- How has geology changed the concept?
- Modern usage describes enclosure rather than a guaranteed cooling sequence; experiments and microscopy show overlapping crystallisation can generate the texture.
Further historical context
Ophite and ophitic inherited an older snake-skin visual analogy; nineteenth-century microscopists specified the actual feldspar-in-pyroxene relationship in dolerites.
Petrographic sections disclosed a recurring contact geometry requiring distinction from simply adjacent pyroxene and plagioclase grains.
Plagioclase laths fully enclosed by optically continuous clinopyroxene; some early authors disagreed over breadth of the term.
Modern usage describes enclosure rather than a guaranteed cooling sequence; experiments and microscopy show overlapping crystallisation can generate the texture.
Editorial qualification
Do not automatically infer that pyroxene crystallised strictly later than all plagioclase.
Related names
Sources
- International Ocean Discovery Program, Expedition 360 methods — Operational definitions for igneous groundmass, flow and inclusion textures
- Geological Survey of India, Rock Texture Atlas — Photomicrographs and modern texture definitions
- British Geological Survey, Ballantrae memoir glossary — Historic descriptions of porphyritic rock and textural terminology