Silver bracelet with six large onyx cabochons and inlaid marcasite stones.

Gross Weight: 1.205 ozt. 

Box Size: 8 x 2 x 1 1/4 in. 

Bracelet Size: 7 1/2 x 1 in. 

#2345 #18 . 

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.

The mineral marcasite, sometimes called “white iron pyrite,” is iron sulfide with an orthorhombic and brittle crystal structure. On fresh surfaces, it is pale yellow to almost white and has a bright metallic luster. It tarnishes to a yellowish or brownish color and gives a black streak. In the late Medieval and early Modern eras, the word “marcasite” was often used as a catch-all term for iron sulfides in general, including both true pyrite and the mineral marcasite itself. The narrower, modern scientific definition for marcasite as orthorhombic iron sulfide dates from 1845, although to this day the jewelers’ sense for the word hews closer to the terminology that pre-dates this scientific redefinition. Marcasite is found all over the world, particularly in low-pressure, highly acidic locations, and geological research on the origins of the mineral have been instrumental in understanding the development of carbon-based life on Earth. Marcasite reacts more readily than pyrite under conditions of high humidity, disintegrating into iron sulfate and sulfuric acid, so low humidity storage conditions for marcasite jewelry are necessary to prevent or at least slow down the reaction.

Slight discoloration to silver. Overall good.