100v - - - - - Gemstones
Take white pebbles that are found along rivers & along gravel banks, & paths and that are somewhat transparent. If they are perfectly transparent, & it will be better. If not, use the best & whitest ones that you can find. Calcine them three or 4 times in your four à vent & quench them in water or vinegar. Then, take a ℥ of them and pound them in a completely pure copper mortar, & with a pestle of pure copper, and grind them until they become very fine & soft powder; this is a sign that they have taken enough of the substance ofcopper to give them greenness. Then in your ℥ of pebbles, add in three ℥ of good minium, unadulterated by brick & something else, and strongly pound everything together again in a bronze mortar. And in all of this, add in a gros pour ℥ of sel de verre, & some & the common people put in sandever that they find it among the glassmakers or apothecaries. But alkali salt, as you know, is better.
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Emerald In this way, the vulgaire makes emeralds & casts them in sand. If you do not have a bronze mortar, crush avecqun mort in a cauldron of pure copper.
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The cruciblesneed to be reheated before putting materials in, and need to be put in the forge or four à vent instead of making & increasing the fire. Figure
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They are done in an hour & a half.
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A gros of salt in four ℥ of pebbles &minium. When one says: for ℥, what is to be understood is: an ℥ of body & not of salts & minium.
For ruby take goldin leaves
Raise your stove by two tiles all around because more heat is needed to make rubies than emeralds. And take an ℥ of white, calcined pebbles, and put it in a glass mortar &, having roughly pounded it with the same kind of pestle, mix un grain in the weight of a grain of gold leaves of the kind used by painters for gilding, & crush.
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Some say that mixing the gold with pebbles and saltpeter gives the color of a peach tree . at left bottom margin
Others say that the gold has to be cemented several times and then beat into leaves.
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