|  | Gems 
 
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	     |   | Agate 
                
		 
                
                  | Color: | White with variations of brown concentric bands.. |  
			
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           | No gemstone is more creatively striped by nature than agate, chalecedony quartz that forms in concentric layers in a wide variety of colors and textures. Each individual agate forms by filling a cavity in host rock. As a result, agate often is found as a round nodule, with concentric bands like the rings of a tree trunk. The bands sometimes look like eyes, sometimes fanciful scallops, or even a landscape with dendrite trees.. |  |  | 
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