Al Qalb is the eighteenth lunar mansion, spanning roughly 218 to 231 degrees within Scorpio, and it contains the red star Antares, the Scorpion's heart. Its name means the heart. Antares is one of the four royal stars of Persian astronomy, and the station carries that weight. In the manazil tradition its planetary ruler is Mars, fittingly, since Antares is the rival of Mars, its red glow resembling the planet, and its traditional talismanic virtue is discord and sedition, a mansion assigned to conflict and the undoing of bonds. Each of the manazil carries a fixed magical property from the Arabic tradition, transmitted through the Picatrix and Agrippa. These are the conventions of that talismanic tradition; the underlying star is Antares, a red supergiant long treated as ill-omened.
Al Qalb's identification of Antares as the Scorpion's heart is one of the oldest attested readings of this star across multiple independent traditions, Mesopotamian, Greek and Arabic alike, and its Arabic epithet as rival of Mars, on account of its ember-red colour, is preserved directly in the Greek name Antares itself, anti-Ares, showing a rare case where the Arabic and Greek fixed-star traditions converged on essentially the same figure of speech for the same star through what appear to be independent routes rather than direct borrowing. As one of the four Persian royal stars, Antares carried a weight in the wider astrological tradition that this single manazil station only partially reflects, its talismanic virtue of discord and sedition drawn from the mansion scheme's own separate logic rather than from the star's broader royal reputation.