Black onyx, chalcedonic quartz, is the color of deepest space. Found in both the old and the new worlds, onyx has long been prized for jewelry and precious objects. Its chief virtue as an amulet is that it seems to attract and absorb negative humors from the body of the wearer, causing relief from both physical pain and mental anxiety. Black onyx, suggesting the presence of all colors and the absence of light, serves as a buffer from pain, a defensive wall against evil and illness. Its rich tones provide dramatic contrast for the warmth of red jasper, creating a jewel of both visual and spiritual power. For centuries, coral-- like pearl, a gift of the sea-- was classed among the precious gems valued by man. Not strictly a mineral, coral is an organic substance, composed of the skeletons of millions of tiny marine animals. In its natural state, coral is plantlike in appearance, and grows in warm water at depths of up to 90 feet. In hue, it varies from white, to pink, to red or orange, to black. Coral jewelry is known from the Egyptian, biblical, classical and Islamic periods. Coral is used as a heart stimulant, as an antidote for fevers and toxins in the body, and for preventing vomiting, colic, and childhood diseases. Its mysterious strength seems to derive from its organic source material, the accumulated energy of living things.