Crystal Test on Building Stone

Crystalline Test:

Crystallization test is Conduct to determine the durability or weathering quality of the stone.

• Take four Cubes of stone with side of 40mm
• They are dried for 3days and weighed.
• A sample of stone immersed in 14% solution of Sodium sulfate for 2 hours at room temperature.
• They are dried at (hot air) 100 degree C and weighed.
• Difference in weight is noted.
• This procedure of drying, weighing, immersion and reweighing and repeated at least 5 times.
• Each time, change in weight is noted and it is expressed as a percentage of original weight.

Crystallization of CaSO4 in pores of stone causes decay of stone due to weathering.

But as CaSO4 has low solubility in water, it is not adopted in this test.