ANS:A - the presence of soluble matter of stone

Tests on stone (Strength and Durability Tests).

Acid test (presence of calcium carbonate in building stone. If the edges are broken and powder is formed on the surface, it indicates the presence of calcium carbonate.

Attrition test ( (his test is done to find out the rate of wear of stones, which are used in road construction. The results of the test indicate the resisting power of stones against the grinding action under traffic. ).

Crushing test.
Crystalline test (Crystallization of CaSO4 in pores of stone causes decay of stone due to weathering).

Freezing and thawing test.

Hardness Test (Coefficient of hardness = 20 " (Loss of weight in gm/3).

Impact test (For determining the toughness of stone, it is subjected to impact test in a Page Impact Test Machine).

Smith's Test (Presence of earthy matter will convert the clear water into dirty water. If water remains clear, stone will be durable and free from any soluble matter).