At 10:21 08-02-1999 -0700, you wrote:
>In amongst a box of assorted and mostly unlabeled shells that what given
>to me is one that was labelled as a "Lilac Cowry".  I can't see anything
>like it an any shell book available. It looks like a Tiger Cowry with a
>purplish top instead of spots.  In fact it looks as if someone has
>removed the spotted top of the shell to a layer underneath and then
>smoothed off the edges where the new purplish areas meet the spotted
>edges.  Am I right?
>There is also an unnamed medium sized abalone that has a smooth and very
>shiny iridescent and brown outer surface.  I don't know of any abalones
>that have shiny, smooth shells. This has been polished, right?
>
>Just thought I'd check before I toss them....
>
Some years ago travelling in Thailand I bought one cypraea tigris and one
cypraea mauritiana in Phuket Is.similar to your on top purple cypraea; I
was later told that for turistic purposes they use some
kind of acid (sulphuric ?) on the top of those shells (putting them
bottom up) to obtain that purple color.