What gems were more valuable in antiquity, and why did they depreciate?
Two thousand years ago, "reading stones" were incredibly valuable. Never heard of such, no?..
The ancients called the "reading stone" very large, uniformly weakly colored, polished and transparent - "pure water", as the jewelers say - specimens of gems, most often rock crystal and especially emerald. For one such stone, the ancient rich were ready to give a whole mountain of gold! Have you guessed what this is about?
Here is what the ancient Roman scholar Pliny the Elder writes about emeralds ("smaragdas") in his book "Natural History":
“They're usually concave, so they focus on vision. And those emeralds that have a flat shape, on the same basis as mirrors, reproduce images of objects upside down. Princeps [Emperor] Nero watched the battles of gladiators in emerald."
“Wait, wait! - the most ingenious will say. "It's a lens!" Absolutely right. The very first lenses were made from precious stones - there were no other materials for lenses in ancient times! The glass of that time was very cloudy.
For thousands of years, the “reading stone” was the only way for people with low vision to see something in the distance or, for example, to read a book. Driving such a stone along the lines was, of course, inconvenient - however, there were simply no other ways to help visually impaired people. This continued until, at the end of the 13th century, glasses were invented in Italy.
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In those years, people perceived glasses as a real miracle. The Dominican monk Giordano da Pisa wrote in 1306:
“Not even twenty years have passed since the art of making eye glasses that improve vision arose. And so not far is the time when this new art, hitherto unprecedented, was invented. I personally saw the person who made this invention and talked to him."
By the way, the inventor of glasses unknown to us at first kept his invention a secret! His secret was revealed by another Italian monk, Alessandro della Spina:
"Glasses for the eyes, which were first invented by someone who did not want to reveal a secret to anyone, the venerable brother Alessandro della Spina began to make and distributed to everyone with a kind and joyful heart."
The first known image of glasses is a portrait of Cardinal Hugo de Saint-Cher, Bishop of Ostia, a famous scribe and librarian, painted in 1352. However, the glasses of that time were made exclusively with convex lenses - that is, they helped only with hyperopia. "Minus" glasses, that is, glasses for myopia, appeared only 300 years later, in 1604, thanks to the works of the famous astronomer and mathematician Johannes Kepler.
So are precious stones "forever"? As you can see, the "reading stones" of antiquity, which cost just incredible money, have now turned into ordinary glasses, inexpensive and comfortable.
