from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A variety of silica that contains microcrystalline quartz.
- n. A siliceous rock of chalcedonic or opaline silica occurring in limestone.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Massive, usually dull-colored and opaque, quartzite, hornstone, impure chalcedony, or other flint-like mineral.
- n. A flint-like tool made from chert.
from the GNU version of the Collaborative International Dictionary of English
- n. An impure, massive, flintlike quartz or hornstone, of a dull color.
from The Century Dictionary and Cyclopedia
- n. A cryptocrystalline variety of quartz, also called hornstone, petrosilex, or rock-flint.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. variety of silica containing microcrystalline quartz
Origin unknown.(American Heritage® Dictionary of the English Language, Fourth Edition)