Marked 10k & Onyx Ring. Initial K on top. Onyx. Marked 10k on interior. 

Condition: Good. 

Size: 7/8 x 1 in. 

Ring Size: 9 1/2 

Gross Weight: 4.0 dwt. 6.3 g. 

#3698 . 

Onyx is the parallel-banded variety of chalcedony, a silicate mineral. The colors of its bands can range from a rich black to almost every color of the spectrum. The original word in Ancient Greek means “claw” or “fingernail.” Solid black onyx is perhaps the most famous variety, but is not as common as onyx with colored bands. Artificial onyx types have also been produced from common chalcedony and plain agates. The first-century naturalist Pliny the Elder described these techniques being used in Roman times. Treatments for producing black and other colors include soaking or boiling chalcedony in sugar solutions, then treating with sulfuric or hydrochloric acid to carbonize sugars which had been absorbed into the top layers of the stone. These techniques are still used, and heating and treatment with nitric acid can also be used to lighten or eliminate undesirable colors. Onyx can be found all over the world, and has a long history of use for hardstone carving and jewelry, where it is usually cut as a cabochon or into beads. Onyx was used in Egypt as early as the Second Dynasty to make bowls and other pottery items, and is mentioned in the Bible many times.

Good.