Onyx

Carving cameos in onyxes to just the right depth to reach desired colors is very challenging, especially when the stones have very thin color layers. In this sardonyx cameo from the 18th century, the carver cut through the red layer on some of the lion's tail and rear leg. Although not the case in this piece, dyes could be used to match the color of exposed areas to the desired layer. 17.1 x 25.5 mm, Italian. The Milton Weil Collection, 1939. Metropolitan Museum of Art, New York. Public Domain. (Cropped to show detail).

Article: Onyx Value, Price, and Jewelry Information

Credit: Metropolitan Museum of Art