New method solves old mystery: Hafnium isotopes clinch origin of high-quality Roman glass

Image: A single of the colourless Roman glass sherds from Jerash, Jordan, analysed in this examine. Purple splashes are iridescence thanks to weathering.
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Credit rating: Danish-German Jerash Northwest Quarter Venture.

Glass is an immensely fascinating archaeological content: Though its fragility and splendor is intriguing in itself, geochemical scientific tests of invisible tracers can expose more than what meets the eye. In a new worldwide collaboration examine from the Danish Nationwide Analysis Foundation’s Centre for Urban Network Evolutions (UrbNet), the Aarhus Geochemistry and Isotope Analysis System (AGiR) at Aarhus University and the Danish-German Jerash Northwest Quarter Venture (Aarhus University and University of Münster), scientists have discovered a way to determine the origin of colourless glass from the Roman period of time. The examine is posted in Scientific Experiences.

The Roman glass industry was prolific, making wares for consuming and dining, window panes and colored glass ‘stones’ for wall mosaics. A single of its superb achievements was the creation of big quantities of a colourless and clear glass, which was especially favoured for substantial-good quality slice consuming vessels. The fourth-century Rate Edict of the emperor Diocletian refers to colourless glass as ‘Alexandrian’, indicating an origin in Egypt. Nonetheless, big amounts of Roman glass are identified to have been manufactured in Palestine, where by archaeologists have uncovered furnaces for colourless glass creation. These types of furnaces have not been uncovered in Egypt, and hitherto, it has been very demanding to scientifically explain to the difference involving glass manufactured in the two regions.

Now, an worldwide collaboration led by Assistant Professor Gry Barfod from UrbNet and AGiR at Aarhus University has discovered the answer. Their operate on Roman glass from the Danish-German Jerash Northwest Quarter Venture in Jordan demonstrates that the isotopes of the uncommon component hafnium can be utilized to distinguish involving Egyptian and Palestinian glass and provide persuasive proof that the prestigious colourless glass identified as ‘Alexandrian’ was without a doubt manufactured in Egypt. Two of the co-authors of the publication, Professor Achim Lichtenberger (University of Münster) and Centre Director at UrbNet Professor Rubina Raja, head the archaeological task in Jerash, Jordan. Since 2011, they have worked at the website and have furthered substantial-definition techniques to the archaeological content from their excavations. By way of total quantification procedures, they have over and once more shown that these types of an solution is the way ahead in archaeology, when combining it with in context scientific tests of various content teams. The new examine is yet a different testament to this solution.

“Hafnium isotopes have proved to be an significant tracer for the origins of sedimentary deposits in geology, so I expected this isotope process to fingerprint the sands utilized in glassmaking”, states Gry Barfod. Professor at Aarhus University Charles Lesher, co-author of the publication, continues: “The reality that this expectation is borne out by the measurements is a testament of the personal website link involving archaeology and geology.”

Hafnium isotopes have not formerly been utilized by archaeologists to glimpse at the trade in historic person-manufactured elements these types of as ceramics and glass. Co-author Professor Ian Freestone, University Faculty London, feedback, “These remarkable benefits obviously exhibit the potential of hafnium isotopes in elucidating the origins of early elements. I forecast they will become an significant part of the scientific toolkit utilized in our investigation of the historic economic climate.”

Simple fact box:

The sand along the Mediterranean coastline of Egypt and Levant (Palestine, Israel, Lebanon and Syria) originates from the Nile and is ideal for glass creation simply because it normally is made up of the amount of money of lime wanted to continue to keep the glass steady and not degradable. In the Levant, they manufactured transparent glass by incorporating manganese – it was superior, but not excellent. The next type of Roman glass, which scientists now exhibit arrived from Egypt, the glassmakers manufactured transparent by incorporating antimony (Sb), which manufactured it crystal clear for that reason, this was the most precious glass.


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