A beautiful Ammonite fossil, - two halves, earring pair polished in cross-section to bring out the beautiful pattern of chambers. It comes from Madagascar.
An extra piece for an extra piece of jewelry, just watch out for acids when tinning. They can also be drilled with a small diameter, as for a shell, but a flange is generally more suitable for them.
Ammonite, like other fossils, connects us with the earth and its past, teaches us that everything has a time to be and a time to go. So it is also a stone of its kind for the efficient use of our time here :-)