Cupel 2″ Bone ash, each – absorbs 85 grams of lead!
The Science of Cupelling – Cupelling is a part of assaying, however it can also be used at any time to prove or disprove precious metals. In other words, cupelling can be used as a mini-assay. If you have anything in which you believe might be gold, silver or platinum, it is simple to) grind a small amount of your substance, mix it with some powdered lead or wrap some lead wool around it, put it in a cupel and place it in the furnace. In about 40 minutes you will have a bead of precious metals or no bead as the case may be. This has been an absolute test of gold, silver, and platinum for over 2000 years.
The heated lead oxidizes creating hot litharge, a liquid that destroys all minerals except the precious metals. Everything is destroyed and dissolved and the precious metals are drawn into the lead. The cupel acts as a blotter for the litharge and soon all of the lead has oxidized leaving only the precious metals as a bead on the center of the cupel.