What is the equation for specific gravity?

Specific gravity, also known as relative density, is the ratio of the weight of a substance to the weight of an equal volume of water at a temperature of 4 degrees Celsius. The weight value in the equation can be substituted with the density of that substance.

This equation forms the base of all methods that are used in the concentration of ores. Some of these techniques, such as jigging, panning, spiral separation and shaking, depend on the differences in specific gravity of each substance in obtaining concentrated ore. This is because specific gravity is highest in rocks rich in magnesia, iron and other heavy metals.