Stone's names: Onyx, Sardonyx (with white and brown bands).
Color: The layers in these stones range from translucent to opaque for sardonyx. The stones vary in color, too. They may be white or gray, ranging to many colorful varieties. Sardonyx stones usually contain flat-banded, white and brownish-red bands. Onyx is a gemstone with alternating light and dark bands, which are colored in brown, red, black, white and grey.
Description: SiO2 Onyx is striped, semiprecious variety of the silica mineral agate with white and black, brown or red alternating bands. Its properties are the same as those of quartz.
Birthstone: Sardonyx is the birthstone of Leo (Lion): July 23 - Aug 22.
Wedding anniversary: Onyx is the anniversary gemstone for the 7th year of marriage.
Black Onyx is the anniversary gemstone for the 10th year of marriage.
The name's origin: The word Sardonyx is derived from the Greek, Sard meaning "reddish brown," and onyx meaning "veined gem."
Varieties: Varieties of onyx include carnelian onyx, with white and red bands, and sardonyx, with white and brown bands.
Care and treatment: Onyx may chip or scratch rather easily, so store onyx carefully and never allow two specimens to touch each other.
From the stone history: The name onyx was used by the Romans for a variety of stones including alabaster, chalcedony, and what is now known as onyx marble. Roman soldiers wore sardonyx talismans engraved with heroes such as Hercules or Mars, god of war. They believed that the stone would make the wearer as brave and daring as the figured carved on it. During the Renaissance, sardonyx was believed to bring eloquence upon the wearer and was regarded with great value by public speakers and orators.
Cameos are cut from stones, such as onyx, sardonix or agate, where different colors occur in layers. The background material is cut away, leaving the cameo design in relief. Onyx is also used in intaglios because its layers can be cut to show a color contrast between the design and the background.
Sardonyx at one time was more precious than gold, silver, or sapphire. Sardonyx is always widely used in cameos and intaglios.