As a member of the quartz mineral family, Jasper stone is composed of silica which gives this stone an opaque appearance. Does not matter which type of jasper you consider, each and every jasper specimen contains tiny quartz crystals that have gained a distinct color and pattern because of mineral impurities present in trace amounts, such as the presence of iron in the case with red jasper. On the Mohs Scale of Mineral Hardness, jasper ranks 7, which makes it a dependable stone in the field of jewelry making.