🜔 is the alchemical glyph for the Philosopher's Mercury (Latin: Mercurius Philosophorum), the purified, spiritualized, and 'fixed' mercury that is the essential agent of transmutation. Unlike common quicksilver (☿), which is volatile and base, 🜔 represents the Aqua Permanens—the universal solvent that dissolves all metals into their prima materia, and the coagulant that reunites them into the Philosopher's Stone. The symbol itself is a crucible (the vessel of transformation) surmounted by a cross or bar, signifying the union of the fixed (sulfur) and volatile (mercury) principles, the Rebis in its initial, potential state.

Position on the Tree of Life

On the Alchemical Tree of Life, 🜔 corresponds to the third sephirah, Binah (Understanding). Binah is the receptive, formative principle, the Great Mother who gives structure to the raw energy of Chokmah. As the 'Mercury of the Philosophers,' 🜔 here represents the prima materia after it has received the first imprint of form—the 'fixed' mercury that will become the matrix for the Stone. It is the Materia Prima in its most refined, spiritualized state, the 'Virgin Earth' from which the Lapis is born.

Astrological and planetary correspondence

Astrologically, 🜔 is linked to the planet Mercury (☿) but in its 'exalted' or 'philosophical' condition. It is the Mercurial principle purified of its volatile, unstable qualities, corresponding to the fixed, essential nature of the metal. In the alchemical schema, this is the 'Mercury of the Wise'—the spiritual, animating force that mediates between the celestial and terrestrial realms. It is not the common planet but its virtus or anima, the 'Spirit of Mercury' that is the key to all transmutations.

Historical context

The symbol 🜔 appears in numerous alchemical manuscripts and printed works from the late medieval period onward. It is a variant of the standard mercury symbol (☿) but with a horizontal bar or cross, indicating its 'fixed' or 'philosophical' state. The earliest known use is in the Rosarium Philosophorum (1550), where it is described as the 'Mercury of the Philosophers' that 'dissolves and coagulates' the metals. The 17th-century alchemist Michael Maier, in his Atalanta Fugiens (1617), uses 🜔 to denote the Aqua Permanens that is the 'bath' in which the King (gold) is dissolved and reborn. The symbol is also found in the Mutus Liber (1677), the 'silent book' of alchemical emblems, where it appears on the crucible of the opus. In the Theatrum Chemicum (1602-1661), 🜔 is explicitly linked to the Lapis Philosophorum as its 'seed' or 'sperm.' The 19th-century occult revival, particularly through the Hermetic Order of the Golden Dawn, codified 🜔 as the 'Mercury of the Philosophers' in their alchemical correspondences, placing it at Binah on the Tree of Life.

In the table of Liber 777, 🜔 appears at step 3 (Binah) of the Alchemical Tree of Life (i.) scale. It is the 'fixed' mercury that is the matrix of the Stone, the Materia Prima in its most refined state, and the essential agent of the Great Work.