from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A dense, homogeneous rock with constituents so fine that they cannot be seen by the naked eye.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Certain dark igneous rocks having grain so fine that the individual crystals cannot be seen with the naked eye.
from the GNU version of the Collaborative International Dictionary of English
- n. A very compact, dark-colored �ock, consisting of hornblende, or pyroxene, and feldspar, but neither of them in perceptible grains.
from The Century Dictionary and Cyclopedia
- n. 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.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. fine-grained homogeneous rock (such as basalt) containing minerals undetectable by the naked eye
From Greek aphanēs, unseen : a-, not; see a-1 + phainesthai, phan-, to appear, passive of phainein, to show; see phenomenon.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek ἀφανής (aphanēs, "indistinct, unseen, obscure"). (Wiktionary)