Sardonyx is an alternative birthstone for August along with Peridot and a planet gemstone of Saturn. Birthstone. Sardonyx is for the astrological sign of Leo (Lion): July 23 - Aug 22. It is the anniversary gemstone for the 10th year of marriage.

Sardonyx is a type of (cryptocrystalline quartz or SiO2) agate (micro-crystalline chalcedony quartz) that forms varying striped veins of orange brown and white stripes like the banded ring patterns of cut tree trunk, formed by different shades of agate filling the space in a rock. The name Sardonyx derives from the word "sard" and "onyx" is named after Sardis where it is found and Onyx is the Greek word for "nail" because its veined appearance resembles a fingernail. It has beautiful bold banding of opaque and translucent colors white, black, green and orange.

The seals used in Rome were made from Sardonyx they believed it could fire up courage and bring victory in battle. Sardonyx was often carried into battle carved with images of deities and heroes such as Hercules Ares, or Mars, the soldiers thought they would become as brave as the gods and heroes carved them. Leaders and public speakers carried them as well to bring them luck in making the listener see there side.

Sardonyx is carried to fortify willpower and integrity and is known as a stone of protection and strength. It has been used in making a gem protection grid putting a stone at each corner of the house to keep out crime and negativity. Ancients believed it to enhance commitment, stability and happiness in marriages.

An old rhyme about this gem:
The August maiden,
with sweet simplicity wears Sardonyx,
gem of felicity.