1 Apply Aloe vera gel or juice: Aloe vera gel or juice helps get rid of acne scars and makes your facial skin healthier. 2  There are many brands of aloe vera gel or juice available on the market today.
Jupiterimages/Photos.com/Getty Images. Limestones are a class of sedimentary rocks composed of the same mineral, calcite, which is made from calcium carbonate, or CaCO3. Despite this similarity in composition, however, not all limestone rocks are the same. Chalk is actually a special form of limestone that exhibits some differences from other rocks in the same class.
Over the course of geologic time, the layers of calcium carbonate are lithified and converted into rock. Chalk is a variety of limestone which is composed primarily of the shells of single-celled, calcium carbonate secreting creatures. Think about this next time you use chalk - that white stuff all over your hands is actually countless individual shells, each microscopic in size and the former home of a living being.