Sardonyx & Sardius

Sardonyx

Sardonyx is a variant of onyx in which the colored bands are usually flat-banded, white and brownish-red rather than black.
Use of sardonyx appears in the art of Minoan Crete from the archaeological recoveries at Knossos.
Roman soldiers wore sardonyx talismans engraved with heroes such as Hercules or Mars, believing that the stone would make the wearer as brave as the figure carved on it.
During the Renaissance, sardonyx was believed to bring eloquence upon the wearer and was greatly valued by orators.

Sardius

Sardius is a stone of a blood-red or flesh color and is commonly known as carnelian or sard.
Sard was used for Assyrian cylinder seals, Egyptian and Phoenician scarabs, and early Greek and Etruscan gems. The Hebrew odem, translated sardius, was a red stone, probably sard.
According to Pliny the Elder, sard derives its name from the city of Sardis in Lydia, but it more likely comes from the Persian word sered, meaning yellowish-red. Others say it is found in Sardinia, from whence it has its name.