Limestone, a very common sedimentary rock composed of skeletal fragments of marine organisms.
Only available in 10 mm diameter
ECRM752-1-NP
Karbonate
Trace element concentrations in (bio) carbonates are used as proxies in paleo-climate research (foraminifera, corals, pteropods, mussel shells, red algae, stalactites, etc.), serve as proof of origin (corals, otoliths), etc.
