In fact, Onyx and Agate are the same stones. They both are just the varieties of chalcedonic Quartz. However, Onyx and the Sardonyx contain different bands arranged in parallel layers.

The name "Onyx," apparently, is derived from the Greek word that means a fingernail, referring to its brilliance similar to Human fingernails. Sardonyx got its name thanks to the brownish-red colored layer of Carnelian, also called "Sard." This term, in turn, has its roots in the Greek word "Sardis," that means "flesh," on account of its color.

Brief History

Onyx crystals first came from India. This gem was in demand in ancient time because the ancients used it to create cameos and for various adornments of the vessels.

Pliny frequently mentions Onyx in his treatises. For instance, he described 30 columns of immense size made of Onyx set in the banquet-hall of Callistus. He also described that the Hindu Fakirs worn rosaries made of onyx beads in his time. He also mentioned 2000 cups made of Onyx in possession of Mithridates. The archaeologists found Numerous engraved onyxes, dated 400-300 BC, during the excavation of temples and tombs on Cyprus.

Unfortunately, Onyx lose its value after the invention of the artificial method of producing. This approach appeared in Germany as a part of an agate preparation industry.


In the Middle Ages, people believed that Sardonyx could cure epilepsy. However, the ancients split Sardonyx and Onyx. Onyx, in turn, symbolized happiness in marriage. The ancients thought that Onyx could bestow its owner with oratory. We also may find the mentions that Onyx prescribed to be worn around the neck as a mascot. Thus, this gem will calm the passions, and assist in avoiding strife.


The principal deposits of Onyx are in India, Yemen (Asia Minor), Russia, Germany (Oberstein and Idar), Ireland, and South America.

Indian onyxes are much larger than the German ones. Oriental onyxes, in turn, are translucent and much harder.


Onyx is the Birthstone appropriate for July, according to the ancient traditions. Sardonyx, in turn, is a Birthstone for August, according to U.S. Birthstone Chart dated 1912, and contemporary U.K. Birthstone Chart.

Onyx Image Credit to Bence Fördős