Limestone is a carbonate sedimentary rock that is often composed of the skeletal fragments of marine organisms such as coral, foraminifera, and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Calcium carbonate has been used extensively throughout history in construction and agricultural applications, and it is still one of the world’s most widely used materials. Lime (CaCO3) is a strong source of Calcium (Ca) and is used to raise soil pH (reduce soil acidity) which in turn improves the uptake of NPK fertilisers. It is also used in stock feeds, aquaculture, as a neutraliser of acid sulphate soils and as inert fillers in many other industrial applications. Note: This lime is calcium carbonate, it is not hydrated or quick lime.