Assay Cupels/Crucibles

[sanjuangold]

Hello all. Does anyone have any experience or knowledge about metal detecting old assay cupels/crucibles? Or, does anyone know what material the Spanish used for these items? No, I have not read De Re Metallica. Or, should they even detect. I understand that the common material is usually bone ash, but I've also heard of graphite being used. Just not sure if the absorbed lead would be enough to detect.

I have found some material fragments of what appears to be cupel lids (?), with the appearance of graphite (weight-streak-etc.), while looking/detecting around old Spanish camp sites. I am out of country and do not have access to the items or I would post a pic, maybe later.

Thanks for any info.

 

[Real de Tayopa Tropical Tramp]

HIO Sanju, having worked as an assayer in remote regions of Mexico, and having read over and over De Re Metalica, Bone ash is the basic and preferred materiel.

I have no idea how many skeletons of cows that I have burned in a fire for my materials. Yes, I made my own moulds and rams for the bone ash, although I must admit, that when bones were scarce I used small amounts of cement.

I always had to referee each cupel lot to see if any contaminants were added. There were no lids in cupeling or scorifing.

The lead is a fair amount , depending upon your sample. It will always turn the ash yellow. and the cupel will be heavy, but it is not metallic lead. I have no idea if it will react with a detector.

I have never heard of the Spanish using graphite.

Feel free to ask or em me for whatever information that I may provide..

Don Jose de La Mancha