Indian metallurgy, alchemy and tantra

[Dean Anderson]

An archaeologist colleague of mine is studying early Islamic Persian
metallurgy and metallic glazes. He made an interesting comment about how
they set up special academies just to house European alchemists fleeing
Christian persecution. That reminded me of the links I had seen about
Indian metallurgy and alchemy being related somehow to tantra but I
don't know much about it. I mentioned this and he felt that he was
probably seeing some Indian influences in his work but didn't know how
to track them down.

Does anyone have any reputable sources on Indian metallurgy, alchemy and
tantra from about the sixth to the tenth century AD?

Dean Anderson