Is this a fossil seashell or just old?

[-Andy-]

Hi all, I found this sea shell by a Malaysia beach. It was unusual in that of the thousands and thousands of "fresh-looking" shells around, this one looked incredibly old and felt more rock like than shell like. A museum staff examined this and concluded it is a Murex shell that's at best Pleistocene-aged but he admitted he isn't a specialist in sea shells.

 

I asked the FB group, Fossil Seashells and got the following answers:

 

1) Chicoreus brunneus - Max 15 years - Fossils are found deep in sediments or on land in sediments, definitely NOT Fossil

 

2) Some scientists use the term "subfossil" for holocene specimens of species that still exist today

 

3) Old shell , probably a neonate in the 60's, dead in the early 80's, been rolling around/ used as a home base for a lot of marine life since then

 

May I have your thoughts on this?

[Fossildude19]

Looks fossilized, to me.