
~~~~~~~~~~~~~~~100v~~~~~~~~~~~~~~~

Gemstone

Take white pebbles that are found by the rivers &
among the sand bank, & paths, which are
somewhat transparent, & if they are perfectly transparent it
will be better. If not use the best & whitest that you can. Calcine
them three or 4 times in your four à vent & quench
them in water or vinegar. Next, take a
℥ of them and pestle them in a
totally pure copper mortar, & with a pestle of
pure copper, and grind them until they become very fine
& soft powder, and this is a sign that they have taken the substance
ofcopper,enough for giving them greenness. At that time, on your
℥ of pebbles, put in three
℥ of good minium, not adulterated by
brick & anything else, and grind everything together again very
well in a bronze mortar. And on all of this, put in a
grospour
℥ of sel de verre;
& some & the common people put in
esandever that they find at the
glassmakers or apothecaries. But alkali
salt, as you know, is better.

In this way, the common people make emeralds & cast in
sand. If you do not have a bronze mortar, grind
avecqa mort in a kettle
of pure copper.

Emerald



One needs to reheat crucibles before putting in materials, and
put them in the fornaise or four à
vent, before making & increasing the fire.





They are made in an hour & a half.





A gros of salt on the four
℥ of pebbles &minium. When
one says: for ℥, this is to be understood: on
one ℥ of the body & not of the
salts & the minium.




For ruby take some gold leaf

Raise your furnaceby two tiles all
around, because one needs more heat for making rubies than for
emeralds. And take one ℥ of white
calcined pebbles and put it in a mortar of glass;
& having ground it coarsely with the pestle of the same,
mix in grain the weight of a
grain of gold leaf of what the paintersgild, & grind



Some say that, mixing the gold with the pebbles and the
saltpeter, it makes the color of a peach tree
.




Others say that it is necessary that the gold be soldered several
times then beaten into leaf.

