Some readers will know that we spend some time characterizing glass-like properties of proteins obtained by cooling to low temperatures. Well, another kind of glass transition happened in various Iron Age forts in Western Europe. Something heated them up, melted the rock, and on cooling the rock vitrified. Here's one that the admirably knowledgeable John Dye kindly took us to see -The Torr in Shielfoot, Argyll.
Photo: Stephine Smith.
John and his colleagues managed to reproduce the vitrification in the lab using a temperature of 850C.
But why would the ancients have done this? Destruction? Ceremony? Analytical chemistry can tell us nothing about how the temperature was achieved and even less about the motives for the burning.