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Webster 1913 Edition

Noun.

[Gr. [GREEK] invisible;

ἀ

priv. + [GREEK] to appear.]

(Min.)

A very compact, dark-colored [GREEK]ock, consisting of hornblende, or pyroxene, and feldspar, but neither of them in perceptible grains.

Noun.

[Gr. to appear.]

In mineralogy, compact amphibole in a particular state.

aphanite ‎(plural aphanites)

(geology) Certain dark igneous rocks having grain so fine that the individual crystals cannot be seen with the naked eye.