(also amygdale /-ˌdāl/)
A vesicle in an igneous rock, containing secondary minerals.
- Segregation vesicles are therefore distinguished from amygdales because they are infilled with chilled magma, whereas amygdales represent the infilling of vesicles from post-emplacement fluids.
- Some consist of pear-shaped segregation vesicles with amygdales at their upper margin.
- If, after the lava has cooled and set, the vesicles are filled with minerals, they are known as amygdales.
Late 19th century: from French, from Latin amygdala (see amygdala).
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