Specific GravitySpecific Gravity (SG) is the mass of a mineral compared to that of an equal volume of water.

Weigh the specimen in air and record the weight.1)

To determine specific gravity, you need to carry out the following steps:

Specific Gravity2) Note beginning level of water in cylinder (mL), after immersion level of water in cylinder (mL) and difference (mL)

Specific Gravity

3) Volume of mineral sample (cm3) (same as difference, 1 cm3 = 1 mL)

4) Mass of volume of water equal to the volume of the mineral sample (g) (same as difference)

Pure water at 4ºC has a density of 1 g/cm3

Specific Gravity

Calculate density using the following formula:5)

Specific Gravity

Calculate specific gravity (SG) using the following formula:

5)

Note that if a cubic centimeter of a mineral weighs three times as much as a cubic centimeter of water, then its specific gravity is 3.

With a little practice, you can estimate the SG of minerals by lifting them in your hand.

Specific GravityGiven: 1mL = 1cm3 = 1g, we know the weight of an equal volume of water in grams. We can then use the following formula to calculate specific gravity:

Calculation

S.G. = W(mineral) W(water)

Sample ProblemFrom a Public Exam: