What is a stone? Density of stone, types and properties

On Earth, there are thousands of varieties of stones. And beyond all doubt, these are the most widespread formations on the planet, because the Earth itself is a stone covered with a thin layer of soil. The rocks, as we also call them, are quite diverse in their characteristics, composition, value, but, above all, density. This is simply an irreplaceable material used for all kinds of construction, when you choose the right stone. Density in this case becomes a fundamental criterion.

Birth of a stone

Everybody understands that solid rocks did not appear from the air in an instant. For their education, as well as for the birth of all life on the planet, it took millions of years of evolution and special conditions created by nature itself.

Any stone is the hardened magma of prehistoric volcanoes erupting everywhere on the planet billions of years ago, when it was still young and more like the surface of the present Venus. And the process itself, and the conditions, and the influence of many external factors and constantly changing climatic conditions - all this directly affected not only the birth of the stone, but also the formation of its varieties, quite unlike each other.

Therefore, the specialist will determine the density of the stone without any adaptations, knowing only its variety.

The main types of stone

There are only two main types of natural stone - light and heavy, differing, primarily in structure, texture and predisposition to weathering.

Lungs include porous sedimentary formations such as sandstone, limestone, dolomite, rubble stone, and others, which do not have frost resistance, have a high degree of moisture absorption and are highly prone to weathering.

These are types of stone, the density of which is extremely low. They are characterized by looseness, instability and inability to withstand high loads. These types belong to cheap and rather unreliable building materials.

Heavy stone density has a corresponding, it belongs to groups of igneous and (rarely) metamorphic rocks. To them belong: marble, granite, syenite, diorite, porphyry, basalt and many others, the distinguishing feature of which is frost resistance.

Properties of natural stone

It is the resistance to low temperatures that determines the basic quality and quality of the stone. Such rocks are automatically ranked as having a low degree of water absorption, hence they are resistant to weathering.

Frost resistance (freeze cycles) has 9 grades: F10, F15, F25, F35, F50, F100, F150, F200, F300 - it is quite obvious that this is a measure of degrees below zero in Fahrenheit. F10-F50 is a low index characteristic of a light stone, water resistance (softening factor) in it is from 0.9 to 1. Starting from the F100 grade, a heavy stone with high density is determined, it has water resistance values of 0.5-0.75 - These are the indicators characteristic of granite and diorite.

But here it should also be noted that every stone has foreign impurities, and in many respects their density depends on it, because other inclusions make it porous and prone to weathering. This is determined by the Mohs hardness scale and depends on what kind of compressive load the stone is capable of sustaining.

What is the density of the stone

The density of the stone is determined on a scale from 1 to 20, and it is expressed by the ratio of the mass of the rock with a similar mass of water of the same volume. From 1 to 2 light rocks are important, the average density of the stone in this case varies from 2 to 4. All breeds that have a value above 4 are heavy, respectively, and have a high density. Precious stones, such as sapphires, rubies, emeralds and especially diamonds - are the most durable and heavy in this respect, their figure is from 10 to 20.

A similar definition of the density of a stone is expressed in the mechanical action on it - under compression, impact loading and abrasion testing. There is another way to determine the stone for density - by its immersion in heavy liquids. Both methods have nothing in common, so you should consider them separately.

Immersion of a stone in heavy liquids

By immersing a stone in the "heavy water", its density is determined quite accurately and within just a few minutes.

Despite the fact that this method gives a 100% result and takes quite a bit of time, it is used infrequently because of its high cost. The costs of this should be financially justified, therefore, the method is mainly used to determine the density of precious stones, in particular for the detection of counterfeits.

Here everything is simple: the density of "heavy water" and diamond, for example, is the same, and if it is dipped in a synthetic counterfeit, it immediately floats to the surface like a cork. And if the density of a stone of natural origin is equal to the density of a liquid, it does not rise and drown, but remains in a floating state.

Mechanical Inspection Method

By testing mechanically the stone, its density is also determined quite accurately, only in this case rock samples that are not related to precious stones are tested for strength.

This method is quite simple, it does not require special expenses, but it takes a lot of time. For this, a hydraulic press is used, creating a load for determining the hardness of the stone. If the rock is not sufficiently resistant to a certain pressure force or has a porous structure, it will begin to crack and crumble, but if it has the necessary hardness and viscosity, it will remain unscathed.

Mechanical impact methods also include shock loading and strength testing on a cast iron wheel by friction. So to determine the strength of any rock or mineral is very simple, but what is the density of the stone is necessary for a certain type of work - this is a topic of a completely different article.