They have several of those but suggest the spellsilver miners go first; if it gets anywhere it's by far the most valuable.

The spellsilver miners have brought samples of purified spellsilver, in glass vials in oil because it oxidizes, and samples of the sand that spellsilver is most easily purified from, a heavy dark sand called monazite. They can describe their purification process at some length: the ore is washed with acids, precipitated, heated, mixed with salts, and then reduced with bone to get them in metallic form. 

They have several of those but suggest the spellsilver miners go first; if it gets anywhere it's by far the most valuable.

The spellsilver miners have brought samples of purified spellsilver, in glass vials in oil because it oxidizes, and samples of the sand that spellsilver is most easily purified from, a heavy dark sand called monazite. They can describe their purification process at some length: the ore is washed with acids, precipitated, heated, mixed with salts, and then reduced with bone to get them in metallic form. You have to do the process repeatedly to get adequate purity.