In Byzantium there were no academic chemists in the present-day sense of the term - people who carry out laboratory experiments with great precision and attention, and then report their research findings at conferences and in journals. In most cases they were ordinary artisans experimenting with materials to improve the strength and appearance of their devices. Any accomplishments remained within the bounds of the guild they belonged to, and were never made public.
 
Nevertheless, it appears that certain talented royals sought the right to perform experiments… Indeed, 11^th century historian Michael Psellos criticized the then Empress Zoë for transforming her apartments into a perfumer’s workshop: “She lights fires to bake, boils aromatic materials, rubs, pounds, creates substances for perfumes and prepares cosmetics and ointments, instead of weaving, as would befit a woman". Psellos may have said this for fear of an accident, as the empress herself blended all the strange materials brought from the East by Arabs and merchants from Trebizond. His concern was not totally unfounded; artisans involved in such dangerous activities could not set up their workshops anywhere they pleased in the cities, but in specific neighbourhoods, such as Chalkoprateion (meaning “Copper Market”) and the arcades to the north of the Tetrapylon in Constantinople. The workshops in Thessalonica were concentrated around the Church of Panagia Chalkeon.

The emperors lent support to artisans: Empress Irene of Athens granted them financial concessions in 801, and Leo the Wise gave them the right to sell objects made of precious metals and stones, a privilege previously reserved for royal workshops. The raw material for the manufacture of metals (iron, copper, lead, tin, silver and gold) was brought from Eastern Macedonia and Asia Minor (mainly from Paphlagonia, Pontus and Cilicia) as well as from northern Syria. After the 11th century, however, they were limited to the output of smaller mines in the Aegean, Troy in Asia Minor and Halkidiki, the Pangaion Hills and Thassos in Greece. The raw material or mineral ore reaching Byzantium was not pure metal, since processing at production sites was carried out using traditional techniques and methods from the Roman era. Byzantine state officials (public weighers) would test the purity of metals on entry; gold in particular was cleaned by skilled technicians.

A strong tradition in the manufacture of precious metal objects was established in Byzantium. In Late Antiquity there were several production centres throughout the empire (Constantinople, Antioch, Damascus, Tarsus, Cyprus and England). However, from the 10th century onwards gold and silver objects were only made in Constantinople, and possibly also in a handful of other commercial centres such as Corinth and the capitals of neighbouring states. Moulds found in excavations there stand as proof that they wished to emulate the Byzantines and their opulence. Production appears to have declined in mid-Byzantine times – there are no descriptions of precious artefacts in the imperial palace, not even as gifts to foreign rulers. Over the years it seems that there was competition with the West, where the technology for purifying ore by mills and water-powered bellows had already emerged. Financial problems prevented Byzantium from incorporating such devices into the production process.

The difficulty of finding and processing ore led the Byzantines to recycle old metal objects and coins; in areas where minerals were near the surface, it was not uncommon to see peasants picking pieces of metal from the soil. A lengthy process then followed in special workshops: the metal would be melted down, poured into moulds (cast) and then forged into the desired final shape to create sheets or wires. All of the above were done with the aid of fire; manual bellows were used to feed the fire with oxygen whenever the temperature had to be raised. Precious metal utensils were decorated in goldsmiths’ workshops, where skilled artisans gilded and burnished silverware to a shine.

Texts inform us that there was a wide variety of metal workers, such as blacksmiths, coppersmiths, locksmiths, farriers, knife makers, chain manufacturers and, of course, goldsmiths. Archaeologists who have excavated settlements like Rentina have also found old iron foundries: very cramped rooms that often formed part of the house, apparently operating as small family businesses.

Alongside the pursuits of ordinary craftsmen working hands-on, here was the philosophical and theoretical approach taken by alchemists. They sought ways to intervene in and alter the physical properties of a material so as to transform it into something else – to change an ordinary stone into silver or gold, for instance.

This idea that people could change something into something else appears to have originated in the dyeing techniques for wool and fabrics, where the natural colour is changed. It is no coincidence that books of alchemists’ formulas also contain instructions for dyeing with imperial purple. Byzantine alchemists wrote books that replicated older texts, adding magical instructions to them. These were read by very few and had no practical application.