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.
Characteristics of chalk and clay. Chalk: Formed 70 to 100 million years ago, chalk is also called cretaceous limestone.It is a soft, white rock. Chalk is an example of a porous rock, as it has pore spaces, which can store water. It does not have joints and bedding planes like carboniferous limestone. Clay: Is a product of chemical weathering and river erosion. Clay is porous, but becomes impermeable when wet, as the particles expand and fill the pore spaces.