43 - A Second Chalcedony.
1. In 1 pound of nitric acid, dissolve 3 ounces of fine silver, cut into small pieces and put into a glass flask. Seal it well and set it aside.
2. In another glass flask put 1 pound of nitric acid. Dissolve in it 5 ounces of well-purified mercury. Seal the flask well, and set that aside also.
3. In yet another glass flask put 1 pound of nitric acid. In it, dissolve 2 ounces of sal ammoniac. Into this solution,
add ½ ounce of iron crocus made with nitric acid, as demonstrated in chapter 19. Also, add ½ ounce of Spanish ferretto made in the way described in chapter 14, ½ ounce of red copper made in the way explained in chapter 24, and ½ ounce of tinsel calcined with sulfur, as in chapter 21.
All these materials should be thoroughly ground up, each by itself and each powder added separately. One by one put each into the flask, little by little, with patience, being careful with the copper, the Spanish ferretto, and the tinsel since they cause the nitric acid to froth, and swell a lot.
Add each of these with patience, in small quantities over time, since swelling, eruption, and cracking of the glass can occur easily. In order to be successful in this endeavour you must use diligence and patience. When finished, the vessel should be sealed and set aside.
4. In another glass vessel put 1 pound of nitric acid. In it, dissolve 2 ounces of sal ammoniac. lnto this solution put ½ ounce of pulverized crude antimony. Do this little by little, because it will swell and crackle loudly, so pace yourself. Then add ½ ounce of the azure blue enamel that the painters use, 1 ounce of red lead, and ½ ounce of vitriol purified as described above. Everything should be ground well. Finally seal the vessel, and put it aside.
5. In another glass flask, with 1 pound of nitric acid, dissolve 2 ounces of sal ammoniac. Put in 1 ounce of zaffer which is prepared as described in chapter 12, ¼ ounce of prepared Piedmont manganese, described in chapter 13, ½ ounce of thrice cooked copper made with copper sheets calcined inside the arches of the furnace as described clearly in chapters 24 and 25, and 1 ounce of cinnabar. These things I grind thoroughly and add separately into the flask. I take care to be cautious with those things that cause frothing and smoke, and I take my time. When I am done, l seal the vessel and I put it aside.
6. In another glass flask, with 1 pound of nitric acid, dissolve 2 ounces of sal ammoniac as usual. Then add ½ ounce of ceruse [white Iead], this will swell up quite a bit, so you should go slowly. Also, add in ½ ounce of painter's red varnish, ½ ounce of green copper, and ½ ounce of iron flake, which falls from the anvil. This also froths a great deal, so be careful. Everything should be ground up separately. I put them into the flask watching closely. Those materials that cause the nitric acid to froth and smoke, I add cautiously. Finally, I seal the flask and put it aside.
Leave all six flasks to sit for 12 days. Every day agitate them well six times, so that the nitric acid will penetrate, and reduce the metals and other ingredients. This way they will
communicate their tints to the glass. After the prescribed time take a large glass flask which is luted on the bottom. Into it, you should empty all the materials of the six smaller flasks, little by little, so they do not erupt or cause the glass to crack.
In this large flask, stir the acid and other materials well in order to unify them completely. When mixed together well, set this flask in ash, over the slowest of fires, so that in 24 hours the acid will fully evaporate. Take care that the fire is at its slowest at the end, so as not to ruin the powder with too much heat.
lf you want to recover the nitric acid, you can do this by adding a head and receiver. Lure the joints well with the customary bandaging. Evaporate the acid until a tawny colored roasted powder remains in the bottom. Store it in glass, sealed for future use.
Add this powder, or medicine to the glass melt, which is made of broken pieces of old drinking glasses, as was described previously in the first chalcedony recipe. lt will not come out right by using virgin glass frit, but only by using broken glasses, those of crystal will be even better.
Use the same doses as were used in mixing the first chalcedony, and use the same interval between doses as in the other. Add the burnt tartar, the vitrified chimney soot, and the iron crocus made with vinegar into the melt. Add these powders little by little, because as has been expressed before, they froth terribly. Now, I leave it to rest, and at the end of 24 hours I make a test vessel, refiring [striking] it well to see if it takes the proper consistency and opacity, and if it shows the variety of colours with undulations and interplay.
In Flanders, l made many pot-fulls of this kind of chalcedony, which all came out most beautifully. l had all of it worked and made into vessels of various sorts, pinching it off as usual with nippers for each piece, in order to make fantastic variety. Furthermore, I made many hundreds of crowns for the gentry with this chalcedony paste. The work was seen by Grand Duke Ferdinand, of blessed memory, and by many other princes and gentlemen.