This 1,600-Year-Old Goblet Shows that the Romans Were Nanotechnology Pioneers

The colorful secret of a 1,600-year-old Roman chalice at the
British Museum is the key to a super­sensitive new technology that might
help diagnose human disease or pinpoint biohazards at security
checkpoints.

The glass chalice, known as the Lycurgus Cup because it bears a scene
involving King Lycurgus of Thrace, appears jade green when lit from the
front but blood-red when lit from behind—a property that puzzled
scientists for decades after the museum acquired the cup in the 1950s.
The mystery wasn’t solved until 1990, when researchers in England
scrutinized broken fragments under a microscope and discovered that the
Roman artisans were nanotechnology pioneers: They’d impregnated the
glass with particles of silver and gold, ground down until they were as
small as 50 nanometers in diameter, less than one-thousandth the size of
a grain of table salt. The exact mixture of the precious metals
suggests the Romans knew what they were doing—“an amazing feat,” says
one of the researchers, archaeologist Ian Freestone of University
College London.

The ancient nanotech works something like this: When hit with light,
electrons belonging to the metal flecks vibrate in ways that alter the
color depending on the observer’s position. Gang Logan Liu, an engineer
at the University of Illinois at Urbana-Champaign, who has long focused
on using nanotechnology to diagnose disease, and his colleagues realized
that this effect offered untapped potential. “The Romans knew how to
make and use nanoparticles for beautiful art,” Liu says. “We wanted to
see if this could have scientific applications.”