What are the properties of natural stone?

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The most common natural stones are marble, granite, travertine, limestone, slate, sandstone and quartzite. One of the best qualities of natural stones is that no two stones are alike. Because stone is made in nature, its colours vary, making it more beautiful.

When considering using natural stones in your house or in a project, you will want to consider their properties to determine which natural stone is best for the job.

Mechanical Properties

One of the important properties of natural stone is its place on the Mohs hardness scale. The Mohs hardness ranks natural stones on a scale from 1 to 10. If a stone is a 1, it is one of the softest; 10 is the hardest. According to the Granite Land website, the harder the stone is, the less likely it is to be scratched. Limestone measures 3 on the Mohs scale; granite, 6.5; and quartzite, 7.

Young's modulus is another important property of natural stone, because it measures the elasticity of the stones. It measures the amount of stress that can be put on the stone before it deforms. It is measured in gigapascals (GPa). According to the Granite Land website, the majority of natural stones measures about 50 GPa.

Thermal Properties

One thermal property of natural stones is the coefficient of thermal expansion. When a natural stone is exposed to a distinct temperature increase, it causes the stone to expand at a specific rate. The coefficient of thermal expansion for natural stones varies. For example, the coefficient of thermal expansion for quartzite is 1.3, while granite has 7.9 and limestone, 8.0.

Specific heat capacity is another thermal property that tends to be important for natural stones. The specific heat capacity is the amount of thermal energy required to raise the temperature by 1 degree C per unit mass.

Chemical Properties

Acid resistance is important for natural stones. It imparts how much weight of the natural stone will be lost when the stone sits in an acid for a specific amount of time at certain temperatures. Granite is hard and brittle. It can easily withstand acids. On the other hand, marble can be easily corroded by acids.

Natural stones do absorb liquid, but each stone has different chemical water absorption properties. The water absorption of different natural stones is measured by a percentage point. It measures how much weight is increased after the stone was submerged in water at a defined temperature for a specific amount of time. The typical water absorption of granite is .3 per cent, while the absorption of marble is .1 to .2 per cent.