Black Onyx

About this stone

Black Onyx is a deep-black chalcedony that the Greeks associated with strict discipline and the Romans wore to soldier-stones. Astrologically it sits with Saturn and modern Pluto: it favours the long held boundary, the kept promise, the choice not to react. In a synastry context it is the stone for couples whose Mars-square or Mars-conjunct-Saturn keeps producing impulse-and-regret loops.

At a glance

Ruling planet

Saturn

Chakra

Root

Colour

Solid black

Mohs hardness

6.5 – 7

Origin

India, Brazil, Madagascar, USA

Supports

Mars (drive, passion), Hard aspects (squares, oppositions)

How Black Onyx links to the zodiac

This stone is traditionally paired with Leo, Capricorn, Scorpio. Each sign draws on it slightly differently.

• ♌ Leo

  fire · fixed

  Leo uses Onyx as ballast — solar fire still burns, but it stops setting the curtains alight.

  Ruling planet: Sun

• ♑ Capricorn

  earth · cardinal

  Capricorn is Saturn-ruled and Onyx is a Saturn stone — discipline that compounds quietly into authority.

  Ruling planet: Saturn

• ♏ Scorpio

  water · fixed

  For Scorpio, Onyx holds the deep silence so transformation can happen without melodrama.

  Ruling planet: Pluto

Put Black Onyx to work in your chart

Black Onyx is traditionally reached for when the Mars, aspect side of a bond needs support. See where that shows up in your own placements:

• Check your astrological compatibility to find which dimensions of your match could use Black Onyx.
• Generate your free birth chart to locate your Saturn placement.
• Browse all healing gemstones