G’day; There have been a few requests regarding silver. One
that hasn’t come up yet - I’m sure it would have - is how does
one tell the difference between sterling and fine silver? I’ve
mixed them up before now. Well, heat them both. The one that
darkens most is almost certaintly sterling. Want to be more
positive? Dissolve a tiny bit of each separately in warmed
nitric acid, add a solution of common salt and both will give a
white precipitate that turns purple in bright sunlight. Add
ammonia, dropwise. The precipitate dissolves (test for silver)
Continue until the liquids smell strongly of ammonia, and one
will have a blue tinge. Add more ammonia and the blue will
become more apparent. The blue is due to the copper in the
sterling; fine silver of course won’t show this. QED. And
cheers. – John Burgess,