angle of extinction
- noun
- Specialized
:
ángulo de extinción
- Each crystal has a characteristic angle of extinction when analyzed with polarized light.
Examples
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The mineralogist measured the angle of extinction to help identify the crystal specimen.
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Accurate determination of the angle of extinction is essential in optical mineralogy.
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The angle of extinction is crucial for mineral identification.
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Can you measure the angle of extinction accurately?
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Accurate determination of the angle of extinction is essential in optical mineralogy.
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Each crystal has a characteristic angle of extinction when analyzed with polarized light.
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The mineralogist measured the angle of extinction to help identify the crystal specimen.
Synonyms
The angle a crystal must be turned to look darkest under polarized light
Surface Forms
Morphology
angle + of + extinction
The phrase literally names an angle associated with ‘extinction’ — i.e. the angle at which light intensity is reduced — so combining 'angle' (a measure of rotation) with 'extinction' via 'of' yields the angle at which extinction occurs. Although it is a technical mineralogical term, the noun‑of‑noun composition is regular and directly derivable from the constituent meanings, so a learner who knows those words can infer the intended sense.
Etymology
The term angle of extinction comes from the simple image of turning a crystal until the light through it seems to 'go out', which is the idea of extinction. So it means the angle you must turn a crystal to make it look as 'dark' as possible under special light used in a microscope.
