This phenomenon is not uncommon. Voids inside the eggs can be filled by calcite and quartz crystals, resulting in geode-like ...

that's calcium carbonate in the calcite crystal structure, that's a species. But we say no, no, no - there are 10, 15 maybe 20 different kinds of calcite, because the calcite deposited by a shell ...

7. Recrystallization: The original skeletal material has grown into new crystals. The process may be aragonite crystallizing to calcite, as in fossil snails, or it may be the growth of larger crystals ...

The researchers found that of the two calcium carbonite crystal structures found in healthy coral — calcite and aragonite — exposure to microplastics caused the structure of calcite to weaken ...