I have come across a slit shell for sale which has no ID or location data.
It may have come from an old collection and has turned up amongst a large
selection of  low grade shells for the ornament and craft market. The seller
doesn't seem to know much about shells either, as she is not a collector and
sells mainly to people wanting a few pretty shells for the mantlepiece.
Although she suspects it may be quite valuable, she does not know what price
to ask, so is investigating before she will quote me a price.
This looks like a possible golden opportunity if she comes back to me with a
really good price. Being a beginner collector, and not very knowledgable yet
myself, I have no idea what the true value of such a shell would be. I have
only briefly examined the shell at her shop, and I did not have any
reference books with me.
I came home and looked at a few books and it looks like it could be a
perotrochus africana or perotrochus westralis. It is about 5 inches, pale
orange and in reasonable condition, I would guestimate  F to F+.
I have read that a slit shell can be faked. I would love to have any advice
you can offer regarding clues to identify the shell and how one can tell
whether it is a fake or not. Is there a site on the internet where I could
see some good pictures? Also an estimation of the value of the shell with no
data at all.
Many thanks for your input.