The three types of rocks igneous, sedimentary, and metamorphic are all subject to processes that change one rock type into another. The images below show several types of rocks undergoing these processes.
Lime is a soil amendment made by grinding limestone, a naturally occurring type of rock that is very high in calcium. Two types of lime are commonly used in lawns and gardens, agricultural lime and dolomitic lime. Agricultural lime, also sold as garden lime, is made from calcium carbonate.
Test your soil's pH level to determine if lime is needed. A pH test measures the soil's alkalinity or acidity. When the pH is above 7.0, the soil is said to be alkaline; when below 7.0, it is acidic. A pH level of 6 to 7 is ideal for most grasses.