White surfaced sterling

Several years ago, before I began casting my own silver, I had some
pendants cast by a casting house other than the one whose equipment I
eventually bought out. I still have one or two of those pieces in my
stock, and recently got an order for one. It’s been in a heat-sealed
plastic bag since it arrived about 4 years ago. The piece is supposed
to have a very shiny reflective surface with raised detail. When I
took it out of the bag, it had what appeared to be a white “bloom” on
it. It looked almost greasy, but it was still reflective. Deep in the
crevices of the detail it is the proper shiny sterling color, but the
rest of it is much too white. It’s obviously metal, but the metal is
not sterling-silver-colored.

The white appearance wouldn’t go away no matter what I did. I tried
(in order) a Sunshine cloth, a velvet polishing puff, a dip in
Tarnex, and the finest grade of the 3-M flexible bristle brush
attachment on the Foredom (that turned the surface BLACK, which wiped
right off with my fingers). I finally threw it in a small tumbler
with some steel shot for two hours. There was absolutely no change in
the surface color–it remained white.

I went up to my jewelry box and got out the pendant I had kept for
myself (and haven’t worn in over a year). After I cleaned off the
accumulated tarnish, using a sunshine cloth, I found that mine has
also turned white. I’m sure it wasn’t white when I first got it.

These things were supposed to be sterling silver. I’ve never worked
with pure silver. I’m wondering if these pieces were cast in fine
silver by mistake. Does fine silver look whitish when it’s been
melted and poured in casting? (But if it was fine silver, why did my
piece tarnish?) Otherwise, what might cause “sterling” to turn
whitish permanently?

–Kathy Johnson
Feathered Gems Pet Motif Jewelry