Author: Haroon Khalil

This test is conducted for the use of stones in regions where the temperature goes below the freezing point. The test consists of keeping a specimen of stone in water for 24 hours and then placing it in a freezing mixture at –12°C for 24 hours. The specimen is taken out and thawed (warmed) to…

This is a geologist’s test. In this test, a thin section of a stone is taken and placed on a microscope to study the following properties:

This test is different from the field hardness test and the attrition test. This test is carried out in Dorry’s testing machine. A cylinder of 25 mm of the stone is rubbed against a steel disc spindled with coarse sand. The specimen is subjected to a pressure of 1.25 kg/mm2. After 1000 revolutions in the…

The toughness of a stone is determined by the impact test using an impact testing machine. Here, a stone specimen of 25 mm diameter and 25 mm height is placed on the machine. A steel hammer of 2 kg weight is allowed to fall down axially on the cylinder from 1 cm height for the…

This test is performed on the stones which are to be subjected to compressive stress. In this test a cubical specimen of 40 mm side is tested in a compression testing machine. The maximum load at which the stone specimen fails by crushing is noted. Then the crushing strength of the stone is the ratio…

This is also called the abrasion test. This test is performed to determine the percentage of the wear of stones that are used for road construction. This test is carried out in Deval’s Attrition Testing Machine. In this test, a certain quantity of stone is placed on Deval’s Attrition cylinder. The cylinder is rotated about…

Laboratory tests on stones comprise of the attrition test, the crushing test, the freezing and thawing test, the hardness test, the impact test and the microscopic test.

Because of crystallization on reaction with some chemicals, the stones may show a loss of weight and some defects. This test consists of immersing a cubical specimen of 40 mm side in a sodium sulphate solution for 2 hours and then drying it in an oven at 100°C. This procedure is repeated for five times.…

This test is also called Mohs’ scale of hardness test. This is a simple test in which the hardness of the test is based on the hardness of the surface. The surface of the stone is scratched with the help of a pen knife, and the hardness is gauged based on the relative abrasiveness of minerals…

It is a rough test without any rigid specification or procedure. A stone is struck by a hammer to gauge the toughness of the stone. The force required to break the stone reflects the toughness of the stone.