While doom scrolling wikipedia i came across a fascinating phenomenon. Mica as a mineral has unique physical properties in that "individual mica crystals can easily be split into fragile elastic plates.", and an example was given of "books" of mica being deposited in stone and i couldn't help but imagine is as a curio.
We already have Mica as a possible stone, perhaps when mining it (or any igneous or metamorphic rock like granite, schist or pegmatite as it is commonly found there) it can be obtained like a petrified seashell.
Relevant example of what i'm thinking of:
https://upload.wikimedia.org/wikipedia/ ... p.vp9.webm