| |
| | Search Encyclopedia.com (Site not responding. Last check: 2007-10-08) |
 | | quartz quartz, one of the commonest of all rock-forming minerals and one of the most important constituents of the earth's crust. |
 | | Macintosh, Charles Macintosh, Charlesmăk´entŏshand180;, 1766-1843, Scottish chemist and inventor. |
 | | The usual cementing material in sandstone is calcium carbonate, iron oxides, or silica, and the hardness of sandstone varies according to the character of the cementing material; quartz sandstones cemented with quartz are the hardest. |
| www.encyclopedia.com /searchpool.asp?target=Quartz+(Macintosh) (527 words) |
|