Welcome to Stuff to Blow Your Mind, a production of I Heart Radio.

Hi, my name is Joe McCormick and this is The Artifact, a short form series from Stuff to Blow Your Mind,

focusing on particular objects, ideas, and moments in time.

Glass breaks.

Apart from its transparency, the brittleness of glass is its defining physical feature.

And yet since at least as far back as ancient Rome, there have been legends of a mysterious lost technology known as the Vitrum Flexile, or Vitrum Maliabale,

glass that can bend without breaking.

The early medieval Spanish scholar Isador of Seville wrote about this now occulted substance in a vast encyclopedic work called the etymologies, which he compiled toward the beginning of the 7th century.

According to Isador's account, during the reign of Tiberius Caesar, there was an ingenious craftsman in Rome who invented a formula for mixing clear glass so that it was flexible and pliable at room temperature.

The craftsman was brought for an audience with Caesar and presented him with a gift of a glass drinking bowl.

Caesar took the bowl and threw it to the floor.

But unbelievably, it did not shatter.

The craftsman retrieved the bowl and showed that instead the impact had only left a dent, as you might expect from a vessel made out of a metal like bronze.

As if this wasn't amazing enough, the craftsman then produced a hammer from his tunic and proceeded to pound the dent out of the glass, restoring it to its original shape.

From here, I'll quote from the translation of Isador by Stephen A. Barney.

Quote, when he had done this, Caesar said to him, does anyone else know this method of making glass? After the craftsman swore that no one else knew, Caesar ordered him beheaded.

Lest if this skill became known, gold would be regarded as mud, and the value of all metals would be reduced.

And it is true that if glass vessels became unbreakable, they would be better than gold and silver.

Whatever you might accept about the bloody logic of the Roman Emperor, there are basic physical reasons for thinking this story is probably not true.

As common as it is now in beer bottles and car windshields, glass is in many ways an exquisite material. It's transparent, it's chemically non-reactive, it can be beautiful to look at.

When heated in a furnace, it can be molded into almost any shape, and it's usually made primarily of silica sand, which is abundant and cheap.

But the major limitation of its usefulness has always been that traditional silicate glass is brittle. According to Luther Wundercheck, writing for the journal Science in 2019, quote,

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