Jasper, an aggregate of microgranular quartz and/or chalcedony and other mineral phases, is an opaque, impure variety of silica, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron inclusions. The name means "spotted or speckled stone", and is derived via Old French jaspre. Jasper is rated between 6.5 and 7 on the Mohs hardness scale. Jasper is generally associated with inner peace, harmony, tranquility and gentleness.