Opal Chalcedony "eyes-chain" from USA

Chalcedony is a gemstone and a variety of the mineral quartz. The color is almost white to pale blue or dove blue, often with stripes. The stone is also found in shades of apple green (called onyx), pink, red (variety carnelian), brown (called carnelian) and copper color. Repositories are include Brazil, Madagascar, Uruguay, India, USA and UK. The clear blue chalcedony comes from Namibia and is increasingly rare, making the stone increases in value. There were ancient statues of gods carved out of chalcedony again. Some medicinal effects is awarded to chalcedony, viz. Against hoarseness, tonsillitis, vocal cord problems, varicose veins. Chalcedony belongs according to various literature on the zodiac Cancer and Sagittarius.