Over the centuries, the views on what minerals are have been constantly changing. And now, whether we want it or not, we are told about minerals from all sides. If you believe such an “adored” ad for all, they are everywhere, ranging from toothpaste to food for sterilized cats.
So what are minerals? And at present there is no consensus on this concept and disputes are not ceasing. To simplify the existing definitions a little, the answer to the question “What are minerals?” can be formulated as follows: minerals are solids of natural inorganic origin and crystalline structure, the composition of which can be represented in the form of a chemical formula. That is, according to this definition, minerals are substances formed during geological processes and having a certain chemical composition. They can be felt physically, that is, by feeling, measuring, weighing or seeing, even with optical instruments. Based on this, a message about minerals, for example, in cat food, which we hear about in commercials, seems at least an ordinary publicity stunt, and by and large - complete nonsense. Although there really are natural minerals that we encounter every day in everyday life, moreover, without which it is difficult to imagine a full-fledged life. One of them is rock salt (halite).
A very important characteristic of minerals in this definition is their “natural inorganic origin”. Of particular interest is precisely the "natural" origin. There are a huge number of all kinds of chemical inorganic compounds known to chemists, but only a small part of these compounds is found in nature, as corresponding to the presented definition of minerals. The reason is that under laboratory conditions, chemists have the opportunity to create more diverse conditions than existing in real nature, and to collect in one "company" such chemicals that practically do not occur together in nature.
Still continuing to find out what minerals are and what are not, we note that, strictly speaking, artificial diamonds and rubies created in the laboratory cannot be called minerals. It cannot be attributed to minerals, including natural ones (despite their natural origin), and amber and jet known from antiquity, which is a viscous variety of coal. The reason is the lack of crystalline structure.
Many questions to the chemists who classify minerals were raised by mercury - the only metal that occurs naturally in liquid form. Previously, when their composition played a major role in the classification of minerals, mercury was considered a mineral (however, water was also). Now, when the presence of a crystalline structure is added to the definition of minerals, most chemists do not classify natural liquid substances as minerals.
Among the most precious jewelry, we are used to hearing mention of pearls. However, it cannot be called a mineral in any way due to the fact that its structure is heterogeneous. It contains the mineral calcite (calcium carbonate, crystalline substance) and organic substances, each of its components having its own chemical composition.
Currently, the concept of “mineral” is often used both as the name of a whole mineral series and as the name of a single crystal. For example, such a unique property of diamond as its hardness is understood as a general property of crystals of a given mineral species. But when it comes to one of the world's largest Cullinan diamonds, we have in mind a single mineral.