Significance

• Relative density is the ratio that demonstrates how dense a substance is in comparison to a given reference material. For example, if the reference material is rock, relative density compares whether another substance is more or less dense than rock. Specific gravity is another name for relative density, usually used when the reference material is water.
  
  

Process

• The relative density, or specific gravity ratio is found by comparing the density of a substance to a reference material. If the relative density ratio is less than one, the substance is less dense than the reference material. If it's more than one, it's more dense. If the ratio is exactly one, the densities are equal.
  
  

Uses

• Relative density or specific gravity can be used to help gauge how well a substance can float in a fluid. It is also used by geologists or mineralogists to help determine the mineral content of a rock or soil sample.