72 - The Coluor of Lapis Lazuli.
Melt lattimo made with the whitest and softest crystal in a crucible. Once it is well fused, add blue enamel with which painters use to paint. Add it little by little stirring the glass well When the colour Iooks good, leave it to stand by itself in the fire for 2 hours.
Then stir the glass thoroughly again to see if the colour appeals to you, and if it is sufficiently loaded. If not, according to your discretion, it may be loaded with more enamel. When tinted
properly, leave it to stand for 10 hours.
Now stir it and if it is good, work it into vessels, which will closely mimic true Iapis lazuli. Make sure that the lattimo is beautiful and white, as was said. When working these vessels, the glass will froth, which you can minimize by putting sheets of gold leaf into
the pot. That way you will have a glass quite similar to natural lapis lazuli.