Carbonatite sample, close-up. Carbonatite is an intrusive igneous (volcanic) rock, more than half of which is carbonate minerals. Carbonates (such as limestone) are usually sedimentary rocks, and volcanic carbonate lava like this is very rare and often contains valuable minerals, in this case several rare earth elements (REE) and uranium. This sample is from Kaiserstuhl, Germany.
Model release not required. Property release not required.