Are seashells renewable?
renewable are seashell
No, the calcium the earth has is all it will have. It is not renewable. Most of the calcium available is in fossil form (e.g. ancient coral reefs, deposits of seashells, organic ooze) that will take millions of years to be replaced (like coal, petroleum, and natural gas). However it is easy to use calcium from bones and seashells harvested today.
Not necessarily. While nearly all fossils, including seashells, are found in sedimentary rock, most sedimentary rock does not contain fossils. Even then, those fossils will not necessarily be seashells. If you do find a rock with seashells, though, you can be pretty much guaranteed that it is sedimentary.