Jasper is another form of chalcedony quartz and in ancient cultures it was believed to have healing qualities in cases of poison bites. It is usually all the various earth-tones; red, brown, yellow- and also green and gray. The red-green variety is the most common and the most popular. This gem is opaque and can either be multi-colored, with strip-patterns or spot-patterns running across it, or solidly colored in a very fine grain. It is easily recognized because of the startling contrast between its primary color and the blotchy pattern. There are very rare black and blue jasper gems.