It looks like the Murex s.s. may have "slipped through the cracks"!!
The thing is, this is actually common - i get it all the time, but can't
sell it because it can't be identified.  Odd, and a bit frustrating.....

The cone, i think Henk may be right - it does not have the correct shape
for normal quercinus, but i am not familiar with the shape of the Red
Sea variety.

-Ross M.