Jasper a microcrystalline variety of quartz is usually listed as opaque. However light may be seen through small chips of jasper making jasper slightly translucent. Jasper is often red, brown or yellow having been coloured by oxides of iron. Although there are many other colors found in the many verities of jasper. The term jasper is also used for other silicified rocks. Many varieties of rhyolite are often called jasper.