When wandering out and about in the field sometime back in
April, when the air still had quite a chill, and the snow had
not completely gone, I came upon some bits and pieces of
history: a few remains from fire assaying. This was a small
site, not necessarily the location of an actual assay lab, maybe
just a place where someone had dumped some miscellaneous debris.
Here's the biggest, most distinctive chunk I found: part of the
bottom of a fire assay crucible, a crucible used in fire assay
for gold and silver. The inside has a thin coating of what was
once fused ore and flux, now cooled to a greenish glass. I think
the bottom of the crucible holds a vague clue to the
manufacturer of the crucible, and hence to its age, but not one
I know how to decipher. Fire assay / cupellation at Wikipedia -
a fairly abbreviated description of the fire assay process. What
is Fire Assaying? - a more complete description. A Textbook of
fire assaying - by Edward Everett Bugbee, the classic and
complete text on fire assaying. I