This standard covers the laboratory testing procedure to determine the true specific gravity of natural building stones. It requires crushing the stone to a fine powder to eliminate the volume of all pores, allowing materials engineers to calculate the absolute solid density of the stone matrix.
Method of test for determination of true specific gravity of natural building stones
Quick Reference Values
sample preparation sieve size150 micron IS Sieve
sample drying temperature105 ± 5°C
standard test temperature27 ± 2°C
distilled water temperature27 ± 2°C
weighing balance accuracy0.001 g
Key Formulas
True Specific Gravity = (C - A) / ((B - A) - (D - C)) where A = mass of empty specific gravity bottle, B = mass of bottle + water, C = mass of bottle + dried sample, D = mass of bottle + sample + water
Practical Notes
True specific gravity is fundamentally different from apparent specific gravity and bulk specific gravity because the sample must be pulverized (passing 150-micron sieve) to eliminate all permeable and impermeable pores.
It is critical to remove all entrapped air from the sample and water mixture in the specific gravity bottle, typically achieved by gently boiling the water or applying a vacuum.