• WordNet 3.6
    • n aphanite fine-grained homogeneous rock (such as basalt) containing minerals undetectable by the naked eye
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Webster's Revised Unabridged Dictionary
    • n Aphanite (Min) A very compact, dark-colored rock, consisting of hornblende, or pyroxene, and feldspar, but neither of them in perceptible grains.
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Century Dictionary and Cyclopedia
    • n aphanite A very fine-grained variety of diorite (which see), or one in which the component minerals, chiefly triclinic feldspar and hornblende, cannot be distinguished with the naked eye.
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Webster's Revised Unabridged Dictionary
Gr. invisible; 'a priv. + to appear


In literature:

There is greater variety in texture, from fine aphanitic traps up to coarse grained dolerites with feldspars one-third of an inch long.
"History and Comprehensive Description of Loudoun County, Virginia" by James W. Head