The Romans excelled in materials science, famously developing self-healing concrete that has allowed their structures to endure for thousands of years. Among their many achievements, one item stands out: a goblet made from dichroic glass. This special glass changes color depending on the angle of the light shining on it. The goblet, named the Lycurgus Cup, is named after a king in Homer’s Iliad who angered the god Dionysus. While scientists know how to create dichroic glass today, it is less clear how the Romans managed to do so using tools and materials from the 4th century CE.
The artisans infused nanoparticles of gold and silver into the glass, which alter the light that passes through it. This process may represent an early use of nanotechnology, as the metals used are smaller than the wavelengths of light they influence. Lisa Hollands, a technical glass specialist at the University of Sheffield, led a study to recreate the glass from the Lycurgus Cup. In a conversation with the Guardian, she described the glass as almost appearing magical. She explained that when light passes through the glass, the gold and silver particles block blue and green light, allowing only reds and oranges to come through. When light reflects off its surface, the particles scatter the light, resulting in the opaque green color that is visible.
To replicate the Lycurgus Cup glass, Hollands first made glass using the same techniques available to the Romans. This involved using materials that they would have had access to. The next part of the project was lengthy and challenging, requiring experimentation with various oxygen levels and furnace temperatures. One of Hollands’ colleagues noted that the glass’s color was very sensitive to its position in the furnace, making it hard to control. Ian Freestone, an emeritus scholar at University College London, remarked that this sensitivity suggests the Romans may have faced difficulties in controlling the color of their glass, leading him to believe they had exceptional luck with the Lycurgus Cup.
Although dichroic glass has been produced since the 1960s by NASA, the version created by Freestone and Hollands is much truer to the original Lycurgus Cup. Once the team understood the necessary steps, they passed the final touch to glass artist Elliot Walker. Walker created a piece inspired by both the Lycurgus Cup and a well-known sculpture of Atlas holding up the world. In his artwork, he replaced the world with a cup, which shines just like the one displayed in the British Museum today. Smithsonian Magazine reported that Walker’s creation will be permanently displayed at the University of Sheffield’s Turner Museum of Glass.
What do you think about the Romans’ ability to create such advanced materials?
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Source: Good News Network, by Andy Corbley