Physical Formation
Onyx is a parallel-banded variety of silicate mineral chalcedony. It forms primarily in gas cavities within petroleum, metamorphic, or igneous rocks as silica-rich fluids deposit alternating, smooth layers of cryptocrystalline quartz over long periods.

Color: Black with white parallel bands; solid black onyx is often dyed or heat-treated for uniform color
Mohs Hardness: 6.5 – 7
Common Sources: Brazil, India, Madagascar, Mexico, Pakistan, and the United States
Zodiac Signs Associated With: Leo, Capricorn
Chakras Associated With: Root Chakra

Metaphysical Associations
Onyx is widely recognized as a powerful grounding and protective stone. Crystal practitioners work with it to absorb negative energy, build physical stamina, enhance self-discipline, and provide emotional support during times of stress or grief.

Fun Fact
In ancient Rome, warriors wore onyx amulets carved with images of Mars or Hercules to instill bravery and strength in battle.