What do greenhouse gases, pearls, antacids, lasers, cement and sea shells have in common?
What do greenhouse gases, pearls, antacids, lasers, cement and sea shells have in common? They are all related to calcium carbonate phases. Calcium carbonate is one of the most commonly occurring natural minerals. It can be observed in three different forms, calcite, aragonite and vaterite. Figure 1 shows the calcite and aragonite forms. These forms share the exact same chemical formula, but have a slightly different crystal structure and are known as polymorphs. Polymorphs have different energies of activation, dissolution rates and degrees of reactivity. Therefore it is critical to ensure the correct polymorph is present for effective functionality. These polymorphs can easily be detected through X-ray diffraction with the MiniFlex II diffractometer, as seen in figure 2. Aragonite, the orthorhombic polymorph, is commonly found in mollusks and the pearly lining of sea shells and certain corals. Pearls are composed almost entirely of aragonite. So how does this relate to greenhouse gas
