Natural stones are classified according to their mineral content and the process of their formation. Most of these minerals can be identified by their color, hardness and crystal formation. However, wide arrays of minerals are often difficult to identify. Many stones look similar to each other, but are actually different. Good stones are characterized by durability, hardness, strength, amenability to dressing, appearance, and weight, fineness of grain, compactness, porosity and absorption.

Natural stones are classified according to their mineral content and the process of their formation. Most of these minerals can be identified by their color, hardness and crystal formation. However, wide arrays of minerals are often difficult to identify. Many stones look similar to each other, but are actually different. Good stones are characterized by durability, hardness, strength, amenability to dressing, appearance, and weight, fineness of grain, compactness, porosity and absorption.