102 - Another Black Enamel
Have 4 lbs of the above described [chapter 93] enamel base material, 4 oz of tartar, or else gruma from bottles of red wine, and 2 oz of prepared Piedmont manganese. Grind these powders well, and blend them together. Mix them thoroughly with the above base material. Put it into a furnace crucible glazed with white glass.
Make sure that the crucible is large with a Iot of the space, because this material will swell quite a bit. Let it melt, and clarify well, then throw it into water, and return it to the crucible. Let it clarify again, watching to see if the color appeals to you. When the signs are right, remove it as usual and form it into cakes. This will be the most beautiful velvet black for goldsmiths to enamel over metals as usual.