91 - A Marvellous Way, No Longer Used, To Make the Above Paste, and to Imitate Every Type of Gem
I took this method from [the writings of] Isaac Hollandus while I was in Flanders. As far as I know, no one uses it any Ionger to imitate gems. Known to only a few persons by chance, it is quite laborious, yet as large a production as it is, it makes gems of as much or more beauty and grace as perhaps any made anywhere until this day, or at least any shown to me by anyone. I will show this method most clearly, and with so many details, and wamings that one practiced in chemistry will easily be capable, and do the work perfectly.
Take ceruse of lead otherwise called biacca, and grind it most finely. Put it into a large glass urinal, and pour a lot of distilled vinegar over it, covering it to about the depth of one palm. Proceed carefully, because in the beginning the vinegar bubbles, and swells strongly. Therefore, add it little by little, slowly, until the fury and rumbling passes.
Afterwards keep this urinal in sand over a hot furnace, until ⅛ part of the vinegar evaporates. Remove it from the fire, and when the urinal cools, gently decant off the strongly coloured vinegar, saturated with salt [lead acetate]. Put this part aside in a glass vessel, and return the residue of the biacca with new distilled vinegar to a low fire, as before, to evaporate ⅛ part.
Decant the colored vinegar as before, and repeat this operation, with the distilled vinegar many times, until you have extracted all the salt from the ceruse. This will be when the vinegar is no Ionger coloured, and no Ionger has a sweet taste [ ], which usually happens by approximately the sixth time, at which point these coloured vinegars are filtered together with the usual diligence.
Evaporate the filtered liquid from a glass urinal, leaving the salt of lead [lead acetate] dried in the bottom; it will be white in color. Pack this into a luted glass flask and put it in sand. Fully cover it in sand from the neck down, except for the mouth of the flask: leave it opened to the furnace to admit enough heat. Continue to heat the flask for 24 hours.
Then remove the salt from the flask, and grind it. If it is red [minium] like cinnabar then do not return it to the fire, but if you see it is yellowish [litharge] then return it to the fire in the glass vessel, as before, for another 24 hours so that it will become red like cinnabar. Have a good fire but not hot enough to melt it, because then all the hard work and the material will be lost.
Pur this calcined red lead into a glass urinal, and as before add distilled vinegar. Repeat the work as before, in all and for all, until you have again extracted the salt from the dregs and sediment in all or in part. Hold these coloured vinegars in glazed earthen trays to settle for 6
days, so that all sediment and imperfection will go to the bottom. Then slowly filter it, the majority of material in the bottom being unusable.
Now separate this well-filtered vinegar from any sediment and leave it uncovered [to evaporate] in a urinal. In the bottom the intensely white salt of Saturn will be left, which is as sweet as sugar [ ]. Dry it well and dissolve it in common water. Leave this solution in pans for 6 days, so that the sediment will go to the bottom. Now filter this salt saturated water, separate it from its unusable larger part, and evaporate it in a glass urinal.
Left in the bottom will be a salt as white as snow, and as sweet as sugar [ ]. Repeat the dissolution, and filtering, and evaporation with common water three times. This is the required sugar of Saturn. Keep it to calcine in sand in a glass flask or ball in a furnace over a moderated fire for many days. lt will further calcine to a colour that is much redder than cinnabar, and more finely impalpable than sifted grain flour. This is the required true sulfur of Saturn; purified from the sediment, foulness, and blackness that were upon the lead at first.
Now when you want to make pastes for emerald, sapphire, gamet, for topaz, chrysolite, or for a celestial, or other colour, use the same materials, colorants, and doses, that are described above in the other prescriptions. Except, take the present sulfur of Saturn instead of using ordinary minium. Use the same doses, and colorants as have been described above for the other colours.
Always work most punctually, as before. You will have jewels of marvelous beauty in every colour, which by far surpass those described above, made with ordinary minium. Because with this true sulfur of Saturn, they will surpass all others by far more than I can write here, as I have seen and made many times in Antwerp. The pastes made with this sulfur do not have the unctuousness, or yellowishness, that they ordinarily have [with minium], which in time cause them to become ugly. While some blemish quite a bit by perspiration and human sweat, this does not happen with these. Therefore, your tedium is not as great, because of the ample compensation of the work, and effect.