Limestone is a common sedimentary rock, about 10% of the total, and is primarily composed of the fragments of marine organisms such as coral, foraminifera, and molluscs. Its a member of a group of rocks called carbonates, made up largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Limestones are common commercial stones used in aggregates for construction, and in the production of quick lime - used to create Portland cement, a component of concrete.
Limestone is, unlike many rocks, soluble (able to be dissolved) in weak acidic water solutions, like rainwater. This leads to their common dissolution at Earth's surface to form what are termed "karst landscapes", such as caves, or sinkholes. Conversely, new rocks may form from these solutions, such as travertine, tufa, or speleothems like cave stalactites or stalagmites.
Mission 1 Lessons 4, 5 and 6 demonstrate the dissolution, transportation and precipitation of new limestone in water at Turner Falls!