How a citizen science project crystallised school students’ interest in chemistry

Calcium carbonate is the most abundant biomineral (a mineral produced by a living organism) on earth. From seashells to chalksticks it’s a material we stumble across frequently; cracking eggs in the kitchen, while out exploring the natural world, or at the chalkboard in classrooms still resisting the upgrade to whiteboards or interactive displays.

In common with other biominerals, there are a number of different calcium carbonate structures, the three main ones being calcite, arogonite and vaterite. While the formation of each structure is exquisitely controlled by living organisms, the factors that influence the crystallisation process and resulting mixtures of structure types are not completely understood.