| Columbia Encyclopedia. 2001-2008. | | | | jasper, type of quartz |
| | | opaque, impure cryptocrystalline quartz, usually red, but also yellow, green, and grayish blue. It is used as a gem. Ribbon jasper has the colors in stripes. | | |
| | | The Columbia Encyclopedia, Sixth Edition. Copyright © 2008 Columbia University Press. |
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