2006-07-25 15:45:32 · 2 answers · asked by JT 2 in Science & Mathematics ➔ Earth Sciences & Geology
From: www.jewelrysupplier.com
A semiprecious variety of chalcedony quartz that is a used often in jewelry. When chalcedony is variegated with spots or figures, or arranged in differently colored layers, it is called agate; and if by reason of the thickness, color, and arrangement of the layers it is suitable for being carved into cameos, it is called onyx. White Onyx, a semi-translucent white to slightly yellowish-white stone, was often used as a background in Victorian jewelry, especially for cameos.
2006-07-25 16:09:23 · answer #1 · answered by China Jon 6 · 1⤊ 1⤋
The difference is in the layering. Black onyx has large, clear areas with no layers or spots and is suitable for carving into uniform figures or cameos. Black agate has spots, zones, or thin, closely spaced layers that can be seen as slightly different in color or reflectivity.
From a mineral or chemical standpoint they are almost identical.
2006-07-25 23:10:08 · answer #2 · answered by aichip_mark2 3 · 1⤊ 0⤋