A common unit of measure for an object's mass is the metric unit grams. However, mass is often confused with weight, which are similar ideas but different characteristics of an object.
Where the standard unit of measure in pounds will give an object's weight, determining its mass relies on gram measurements. However, mass can be misleading because small objects can have immense masses. This is due to the density of the material making up an object. A highly compact mass can take up little effective space but have a great weight. The discrepancy is a result of its volume, which is reduced due to the compact nature of the matter involved.