Take, for example, this popular science article. Wouldn't using an abudant natural resource as money have devalued their currency? And why wouldn't the ancient Egyptians separate out the fossils that they used as coins from the stone that used as building materials. Would it have been prohibitively difficult? Or were nummulites not used as coins at the same time the pyramids were being built?
More generally, details on usage of the nummulites as currency seem to be scarce. Any details on this topic would be most welcome.
Edit: Phrasing.
Edit 2: Apparently Strabo speculated that nummulites were the fossilized remains of beans that were eaten by those constructing the pyramids [secondary source, with primary citation]. That doesn't seem to directly relate to my question, but it was close enough and interesting enough that I thought I would share.
Many, many, many cultures world wide used shells as money. In Africa, North America and China, shells are an abudant resource. People did not spend their days at the beach picking up shells because it was used as petty cash. Its just that although not difficult at all to aquire, it still really was just not worth peoples time to gather. And even if they did the more people that had shells the less the shells would become worth (because of inflation).
The Miscellaneous Bulletins on the Currency Question in the United States, Volume 6 states that nummulites "may have been used as money" along side many other things at the time. Many people are unsure if nummulites were used at all. However, people can and have used anything they want as currency so anything is possible.