Black Onyx is a guardian stone, absorbing negativity and shielding the spirit with grounding calm. It steadies emotions, clears confusion, and inspires wise choices. For Capricorn, it anchors ambition, offering persistence, balance, and protection of their sensitive core. For Aquarius, it roots soaring visions, turning dreams into reality while shielding empathic hearts. Black Onyx guides both signs toward clarity, emotional harmony, and strength rooted in truth.