Mahogany obsidian is a natural volcanic glass featuring deep black and reddish-brown swirls caused by iron and hematite inclusions. It offers a gentler, warmer grounding energy than pure black obsidian, acting as a stabilizing stone for strength, personal boundary work, and releasing internal limitations. Mahogany obsidian most strongly resonates with the zodiac signs Scorpio, Libra, and Sagittarius