aphanitic

American  

[af-uh-nit-ik] / ˌæf əˈnɪt ɪk /

adjective

1. Petrography. relating to or being an aphanite as opposed to a phanerite.

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aphanitic Scientific  

/ ăf′ə-nĭt′ĭk /

1. Of or relating to an igneous rock in which the crystals are so fine that individual minerals cannot be distinguished with the naked eye. Aphanitic rocks are extrusive rocks that cooled so quickly that crystal growth was inhibited.

2. Compare phaneritic

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Example Sentences

Extrusive igneous rocks have a fine-grained or aphanitic texture, in which the grains are too small to see with the unaided eye.

From Textbooks • Jan. 1, 2017

Explain the difference between aphanitic and phaneritic textures.

From Textbooks • Jan. 1, 2015

Hence, any rock which is compact, crystalline and fine grained, is frequently said to be aphanitic, without implying exactly to which of the principal rock groups it really belongs.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" by Various

There is greater variety in texture, from fine aphanitic traps up to coarse grained dolerites with feldspars one-third of an inch long.

From History and Comprehensive Description of Loudoun County, Virginia by Head, James William