(Image courtesy of South Indian Handicrafts.)
Panchaloha, (also known as Panchdhatu) is Sanskrit for a term in metallurgy (the scientific discipline concerning metals). Panchloha refers to traditional alloys made of five metals considered precious as per the Shilpa Shastra. Certain Vedas (Holy Scripture in the Hindu religion) talk about the arts; even old Sanskrit texts like the Shilparatna (in particular) contain detailed descriptions about the methods and guiding rules behind the making of religious idols.
These five metals are gold, silver, copper, zinc and tin. The ancient text has specifics jotted down, for instance; the equipment to be used in the processes, proportions, stance (of the deities) and their expressions. These were to be strictly adhered to when creating the temple idols.
It is also believed (probably as a result of it being in the scriptures) that jewellery made of this special mix called panchdhatu could have a positive effect on the wearer. It was said to bring to the one who had possession of it, all things good; fortune, peace (of mind), poise, success and stability. You could say that the belief is in the mind of the beholder.