Fashion of the Folly - Shell Buttons

I recently found these buttons on the bank facing the Jake White rugby field.  They are made out of shell (mother-of-pearl).  They look like they were hand carved.  

 2 mother-of-pearl buttons found on Collard's Folly.

Photo by J Meintjes

I did some research, found that in the 19th century they made buttons out of oyster or abalone shells up to the 1930's. 

                                            Oyster shell showing how buttons were cut

                                                       Button cuts

https://tissura.com/articles/mother-of-pearl-buttons

ttp://ancientpoint.com/inf/190124-antique_oyster_shell_for_making_shell_buttons_d30.html

https://www.britishshellclub.org/buttons---llewellyn-jones.html

 So these buttons could be over a 100 years old

                                            Victorian nightgown circa 1900 with mother-of-pearl buttons

https://www.google.com/search?q=victorian+clothing+with+mother+of+pearl+buttons&tbm=isch&ved=2ahUKEwjD2_b0q7LxAhUKrhoKHR-DCCkQ2-cCegQIABAA&oq=victorian+clothing+with+mother+of+pearl+buttons&gs_lcp=CgNpbWcQAzoFCAAQsQM6AggAOgQIABBDOgcIABCxAxBDOgYIABAIEB46BAgAEBhQwNgEWJOfBWD0nwVoAHAAeACAAYQDiAHOXZIBBjItMzcuOZgBAKABAaoBC2d3cy13aXotaW1nwAEB&sclient=img&ei=qZDVYIPjG4rcap-GosgC&bih=750&biw=1707&rlz=1C1AVFC_enZA891ZA891&safe=strict#imgrc=tdTIoKiQSVSdsM&imgdii=YN1PSkWLz0WkWM