On Blondness

Περὶ ξανθώσεως

On Blownness (also known as On Yellowing) is a fragmentary Greek alchemical treatise attributed to Zosimus of Panopolis, composed around 300 CE. The work addresses a specific technical operation central to the alchemical art known as xanthōsis, or the yellowing stage. This process was considered an essential intermediate phase in the transmutation of base metals, representing a progression toward the ultimate goal of creating gold. The surviving text, preserved within later Byzantine compilations such as the 10th- or 11th-century manuscript Marcianus Graecus 299, presents practical instructions for laboratory procedures. These include the heating and combining of substances like white compounds and divine water, made from sulfur and quicklime, to achieve the desired color change. As is characteristic of Zosimus's oeuvre, these technical details are interwoven with a philosophical and mystical perspective, framing the physical transformations as an allegory for spiritual purification and enlightenment. The treatise was intended for initiated practitioners, systematizing the alchemical color sequence—from blackening and whitening through yellowing to final reddening—into a coherent framework that blended Egyptian craft traditions with Greek philosophical thought. Zosimus's writings, including the concepts elaborated in this work, exerted a profound influence on subsequent alchemical tradition. His ideas were extensively copied and commented upon by later Greek, Syriac, and Arabic authors, forming a critical link in the transmission of alchemical theory and practice into the medieval Islamic world and, ultimately, into Latin Europe.