Moijey Fine Jewelry & Diamonds Blog

Brilliantly Layered Sardonyx

Originally published on August 25th, 2017

Updated on April 10th, 2020

August's third birthstone is a unique gemstone, but it is readily available. The third gem is called Sardonyx, a variety of chalcedony. Chalcedony is a cryptocrystalline quartz aggregate with an anamorphic crystal composition. Millions of tiny quartz crystals build the structure; the crystals are so small that a special microscope is needed to see each crystal.

Sardonyx is a variety of cryptocrystalline quartz with alternating layers of either black or white bands with reddish-brown layers of sard. The picture above from the Smithsonian provides excellent examples of Sardonyx. What makes Sardonyx unique from agate, another chalcedony variety is that the sardonyx layers form straight lines, while agates form more organic and curvy bands in their structure. The agates, also from the Smithsonian, in the picture below, are excellent examples of banded agates.

For over 3,000 years, chalcedony has been an excellent gemstone for carving and engraving. It's superior for creating wax seal rings, signet rings, intaglio carvings, and cameos. Sardonyx was a popular choice for cameos and intaglios because of its light and dark layered structure. These cameos from the Smithsonian and the intaglio signet ring are excellent examples.

For seal rings, chalcedony was durable, and wax didn't stick to the seal itself. Signets are gems with a table cut and sometimes a carved design. Table cuts are traditionally in men's jewelry, like this 14K Bloodstone Men's Ringwhich we wrote about in March

Despite Sardonyx readily available and inexpensive, it is a challenge finding fine jewelry that has Sardonyx. Naturally, Daniel Moijueh and I will design a custom piece for you if you want sardonyx jewelry in your collection. Yes, we are that awesome.

We do have fabulous chalcedony products at our disposal— earrings of chrysoprase, which is a beautiful apple green gem that gets its color from nickel. The name "chrysoprase" means Golden Apple in Greek. How about these 14K Chrysoprase Crown Dangle Earrings for the apple of your eye? I couldn't resist saying that.

Thanks for stopping by Moijey. I hope everyone will have a great weekend!