Rock-crystal
Medical men in Rome, in the first century, attested that no better cautery for the human body could be used than a crystal ball acted upon by the sun’s rays,[[310]] and this use of the material seems to have been very general at that time.
In his commentary on Andrea Bacci’s gem-treatise, Wolfgang Gabelchover, the German translator, says that a German name of rock-crystal in his time, the early sixteenth century, was Schwindelstein (“vertigo-stone”), because it was believed to preserve the wearer from attacks of dizziness. Other remedial or physical effects of rock-crystal are also noted. Taken as a powder in dry wine, it was a cure for dysentery, and the physician, Christopher Barzizius, taught that if its powder were mixed with honey and administered to mothers, they would be the better able to nurse their offspring.[[311]]
The following lines by Robert Wilson (d. 1600), a popular sixteenth-century comedy writer, credit amber and rock-crystal with qualities not commonly ascribed to them, although the fancied growth of rock-crystal from a piece of ice probably explains its supposed styptic virtue:[[312]]
Lucre: And if they demand wherefore your
wares and merchandise agree,
You must say, jet will take up a straw;
amber will make one fat;
Coral will look pale when you be sick,
and crystal stanch blood.