Extensive properties are those which depend on the amount of matter present, while intensive properties are those that do not change regardless of the amount of matter present. These are both classes of physical properties. The terms "intensive properties" and "extensive properties" are used when comparing, contrasting and describing chemical substances.
Because intensive properties do not depend on the amount of matter present, they are very useful when identifying chemical substances. Commonly referenced intensive properties include color, odor and luster. Malleability, which is the ability of a substance to be drawn into sheets, is also an intensive property, as is ductility, the ability of a substance to be drawn into wires. A substance's freezing point, its melting point, density,and hardness are all intensive properties. Generally, melting point and freezing point are stated as the temperature at which the phase change takes place at atmospheric pressure.
There are far fewer extensive properties of matter than there are intensive properties. Mass, which is a measurement of how much matter is present in an object, is an extensive property. This differs from weight, which indicates the gravitational attraction of an object to the earth and is also an extensive property. Volume, the amount of space an object occupies, is also an extensive property that varies with the amount of matter present. These properties depend on size because they all deal with measurements of some kind, which can change. For instance, both the mass and volume of an object depends on the amount of material that is used or available. If a diamond is cut, its mass and volume changes; these are extensive properties. On the other hand, the hardness of the diamond does not change, because hardness is an intensive property.