- Hard quartz - Hard stone - Stone age axe material - A massive, somewhat impure variety of quartz, in color
usually of a gray to brown or nearly black, breaking with a conchoidal
fracture and sharp edge. It is very hard, and strikes fire with steel. - A piece of flint for striking fire; -- formerly much used,
esp. in the hammers of gun locks. - Anything extremely hard, unimpressible, and unyielding, like
flint.
- A Hard Building Stone - extremely hard rock - Igneous rock - Igneous rock derails train, e.g. - Quartz rock - Type of rock - A crystalline, granular rock, consisting of quartz,
feldspar, and mica, and usually of a whitish, grayish, or flesh-red
color. It differs from gneiss in not having the mica in planes, and
therefore in being destitute of a schistose structure.
- A vessel of clay or stone. - A wall of brick, stone, or cement, used as a lining, as of a
well, cistern, etc.; a steening. - To line, as a well, with brick, stone, or other hard
material.