The Onyx is one of the most ancient stones in use, known and utilized by the early civilizations for its powerful vibrations and awe-inspiring beauty. This deep red stone marbled with white was a stone reserved for nobles to be used in ceremonies, burial ritual and magic not just that as an amulet on swords, shields, and breastplates and/or gauntlets to protect and strengthen the soldiers in battle.
Source: https://blackonyxgemstone.blogspot.com/2019/09/the-duality-of-black-and-red-onyx.html