Specific Gravity

What Would You Like to Know?

-What is specific gravity?
Specific gravity is the “heaviness” of a mineral. It is defined as a number that expresses the ratio between the weight of a mineral and the weight of an equal volume of water. Water has a specific gravity of 1.

-On what is specific gravity dependent upon?
The specific gravity depends on:

the kind of atoms that comprise the mineral

how the atoms are packed together

You can easily distinguish minerals that have unusually high or unusually low specific gravities, just by the way they “feel” when you hold a sample in your hand.

-How is specific gravity measured?
The steps in measuring the specific gravity are:

weigh the mineral in air (W_a)

weigh the mineral in water (W_w)

use the following equation:

W_a/( W_a – W_w )

the resulting number is the specific gravity
*Note that the specific gravity is a ratio, there are no units.


                

Image copyrighted – from the “Photographic Guide to Mineral Species CD” – used with permission.