There are thousands of varieties of stones on Earth. And without a doubt, these are the most common formations on the planet, because the Earth itself is a stone covered with a thin layer of soil. Rocks, as we also call them, are completely diverse in their characteristics, composition, value, but above all - density. This is simply an indispensable material used in all kinds of construction when choosing the right stone. Density then becomes a fundamental criterion.
Birth of a stone
Everyone is well aware that solid rocks did not appear out of thin air in an instant. For their formation, as well as for the origin 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 that erupted everywhere on the planet billions of years ago, when it was still young andmore 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 influenced not only the birth of the stone, but also the formation of its varieties, completely different from each other.
Therefore, the specialist will determine the density of the stone without any devices, knowing only its variety.
Main types of stone
There are only two main types of natural stone - light and heavy, differing primarily in structure, texture and susceptibility to weathering.
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 susceptible to weathering, belong to the lungs.
These are types of stone whose density is extremely low. They are distinguished by friability, instability and inability to withstand high loads. These species belong to cheap and rather unreliable building materials.
Heavy stone has an appropriate density, it belongs to the groups of igneous and (rarely) metamorphic rocks. These include: marble, granite, syenite, diorite, porphyry, bas alt and many others, the hallmark of which is frost resistance.
Properties of natural stone
It is resistance to low temperatures that determines the main property and quality of the stone. Such rocks are automatically classified 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 an indicator of degrees below zero Fahrenheit. F10-F50 - a low indicator inherent in a light stone, its water resistance (softening coefficient) ranges from 0.9 to 1. Starting from the F100 grade, a heavy stone with a high density is determined, in terms of water resistance it has indicators of 0.5-0.75 - these are indicators characteristic of granite and diorite.
But here it should also be noted that every stone has foreign impurities, and their density largely depends on this, because other inclusions make it porous and prone to weathering. This is determined by the Mohs hardness scale and depends on how much compressive load the stone can withstand.
What is the density of the stone
The density of a stone is determined on a scale from 1 to 20, and it is expressed by the ratio of the mass of rock to the same mass of water of the same volume. From 1 to 2, light rocks matter, the average density of the stone in this case varies from 2 to 4. All rocks that have a value above 4 are heavy, respectively, have a high density. Gemstones such as sapphires, rubies, emeralds, and especially diamonds are the hardest and heaviest in this regard, ranging from 10 to 20.
Such a definition of the density of a stone is expressed in a mechanical effect on it - during compression,shock loading and abrasion testing. There is another way to determine the density of a stone - by immersing it in heavy liquids. Both methods have nothing in common, so it is worth considering them separately.
Immersion of stone in heavy liquids
By immersing a stone in “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 very little time, it is used infrequently due to its high cost. The cost of this must be financially justified, therefore, the method is used mainly to determine the density of precious stones, in particular to detect fakes.
Everything is simple here: the density of “heavy water” and diamond, for example, is the same, and if you dip a synthetic fake into it, it will immediately float 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 will not float or sink, but will remain in a floating state.
Mechanical verification method
Checking a stone mechanically, its density is also determined quite accurately, only in this case samples of rocks that are not related to precious stones are tested for strength.
This method is quite simple, does not require special costs, but it also takes quite a lot of time. For this, a hydraulic press is used, which creates a load to determine the hardness of the stone. If athe 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 unharmed.
Mechanical methods of impact also include shock loading and strength testing on a cast-iron wheel by the friction method. So it is very easy to determine the strength of any rock or mineral, but what density of a stone is necessary for a certain type of work is a topic for a completely different article.
