Jābir ibn Ḥayyān (Geber)

Jabir ibn Hayyan (fl. 8th-9th century), known in Latin as Geber, is the most celebrated alchemist of the Islamic world. The vast 'Jabirian Corpus' (which includes hundreds of treatises) is the primary vehicle through which Hermetic alchemical theory was preserved and expanded in the Middle Ages.

The Science of Balance (Mizan): Jabir's central philosophical contribution was the idea that all material substances are composed of four qualities (Hot, Cold, Dry, Moist) and that the alchemist's goal is to find the perfect numerical balance between them.

Sulfur-Mercury Theory: He formalized the theory that all metals are composed of varying proportions of sulfur and mercury, a doctrine that dominated European alchemy for centuries.

Hermetic Lineage: Jabir explicitly identified himself as a student of the Imam Ja'far al-Sadiq and a follower of the 'Master' Hermes, whom he viewed as the source of all scientific and spiritual knowledge.