New study on how Viking beadmakers recycled glass from Roman mosaics

A study published in the journal Archaeological and Anthropological Sciences reveals new manufacturing techniques on how craftsmen in Denmark recycled glass from Roman glass mosaics during the 8th century AD.

Glass became a scarce commodity during the Early Medieval Period, with mosaics in abandoned Roman and Byzantine structures often looted for the coloured glass cubes called tesserae. A trading network transported them north to emporia towns such as Ribe in Denmark, where they were melted down in large vessels and shaped into decorative beads.

- Advertisement -

Until now, archaeologists have assumed that the beadmakers used the opaque white tesserae as raw materials for the production of white, opaque beads. However, a new study of an early beadmaking worship in Ribe by Aarhus University has revealed that the chemical composition of white Viking beads was produced by crushing gold-gilded transparent tesserae which was then re-melted at low temperatures.

Image Credit : Museum of Southwest Jutland

The melted glass would then be stirred to trap air in the form of bubbles, and then wrapped around an iron mandrel to form the beads. The thin sheets of gold on the tesserae were removed prior to the re-melting process, however, the study shows that some gold still inevitably ended up in the melting pot. This process is indicated by the tiny drops of gold in the white beads, the many air holes (which is why the beads are opaque), as well no chemical colour tracers present.

Traces of gold was also found in the blue beads from the same workshop. Here the chemistry shows that the glassmaker’s recipe consisted of a mixture of the blue and golden mosaic stones.

Mixing them was necessary because the Roman blue mosaic stones contained high concentrations of chemical substances which made them opaque – and therefore ideal for mosaics, but not for blue beads. By thus diluting the chemical substances, the result was the deep blue, transparent glass that we know from Viking Age beads.

- Advertisement -

Claus Feveile, from the Museum of Southwest Jutland said: “These exciting results clearly show the potential of elucidating new facts about the Vikings. By combining our high-resolution excavations with such chemical analyses I predict many more revelations in the near future.”

Aarhus University

Header Image Credit : Shutterstock (Copyright)


- Advertisement -
Mark Milligan
Mark Milligan
Mark Milligan is multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 7,500 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.

Mobile Application


Related Articles

Study confirms palace of King Ghezo was site of voodoo blood rituals

A study, published in the journal Proteomics, presents new evidence to suggest that voodoo blood rituals were performed at the palace of King Ghezo.

Archaeologists search for home of infamous Tower of London prisoner

A team of archaeologists are searching for the home of Sir Arthur Haselrig, a leader of the Parliamentary opposition to Charles I, and whose attempted arrest sparked the English Civil War.

Tartessian plaque depicting warrior scenes found near Guareña

Archaeologists from the Institute of Archaeology of Mérida (IAM) and the CSIC have uncovered a slate plaque depicting warrior scenes at the Casas del Turuñuelo archaeological site.

Archaeologists find a necropolis of stillborn babies

Excavations by the National Institute for Preventive Archaeological Research (Inrap) have unearthed a necropolis for stillborn and young children in the historic centre of Auxerre, France.

Researchers find historic wreck of the USS “Hit ‘em HARDER”

The Naval History and Heritage Command (NHHC) has confirmed the discovery of the USS Harder (SS 257), an historic US submarine from WWII.

Archaeologists uncover Roman traces of Vibo Valentia

Archaeologists from the Superintendent of Archaeology Fine Arts and Landscape have made several major discoveries during excavations of Roman Vibo Valentia at the Urban Archaeological Park.

Archaeologists uncover crypts of the Primates of Poland

Archaeologists have uncovered two crypts in the collegiate church in Łowicz containing the Primates of Poland.

Giant prehistoric rock engravings could be territorial markers

Giant rock engravings along the Upper and Middle Orinoco River in South America could be territorial markers according to a new study.