What is the most impenetrable stone?

There is no such thing as the strongest stone. Just as there is no concept of “just” strength. There is the hardest, most wear-resistant, resistant to shock loads, static loads, bending, torsion, temperature, and so on. These are all strength parameters, but different. And different materials have different properties.
In addition, the concept of “stone” does not exist in science. A purely common name. I’m interestedConnoisseur (278) 12 years ago
The most durable stone on earth is BASALT!
Other answers
obviously a diamond
Diamond is not a stone. It seems to be the strongest adamant.
milli200Sage (17959) 14 years ago
what is this? Lev Panov Student (205) Diamond belongs to non-metals, but to substances since it is a nugget, of any shape, but it is not a stone. Construction brick.
Dmitry EgunovStudent (212) 7 years ago
diamond of course
SeryozhaLSupreme Intelligence (100847) 14 years ago
Is granite worse?
milli200 Sage (17959) naturally!
AlexanderSage (10763) 14 years ago
diamond is the hardest, but this is not strength
milli200 Sage (17959) not clear comment.
Diamond and it’s not obvious, it’s true The strongest known is lonsdaleite. Lonsdaleite is an allotropic modification of diamond.
It is 58% harder than diamond Diamond hardness. 10 on the Maoss scale. but it is fragile, if you hit it with a hammer it will crumble. jade is cooler in this sense. it has a snowball structure. If we use numbers, then among the rocks the greatest compressive and shear strength are (in descending order) diabase, basalt and quartzite.
Granites are much inferior to them in all respects. Durable and hard are different characteristics. Glass is hard, but fragile.
Borazon is also approximately equal in hardness to diamond. fullerene is 100% better than diamond
I think it’s a diamond Without reservation, Fullerite – hardness up to 310 GPa, from those known to us today, after it Lonsdaleite – hardness up to 152 GPa and Wurtzite boron nitride – hardness up to 114 GPa. Diamond is no longer the hardest natural material in the world The hardest stone Diamonds will forever remain the girls’ best friends, but soon they risk losing their favor in the industrial sphere. The precious stone some time ago lost its title of the hardest material in the world, giving way to artificial nanomaterials of slightly greater hardness. Today, a rare natural substance looks set to leave all others behind – it is 58% harder than diamond. Zicheng Pan from Shanghai Jiao Tong University and his colleagues modeled how atoms in two substances supposedly having the properties of very hard materials would respond to a special sensor. The first is wurtzite boron nitride, which has a structure similar to diamond, but consists of different atoms. The second is the mineral lonsdaleite, or hexagonal diamond, made up of carbon atoms like diamond, but they are organized differently.
Modeling showed that wurtzite boron nitride can withstand 18% more impact than diamond, and lonsdaleite – 58% more. If the results are confirmed by physical experiments, both materials will be much harder than any known substance. But it will not be easy to carry out such tests, since both materials are not often found in nature. The rare substance lonsdaleite is formed when meteorites containing graphite fall to Earth, while wurtzite boron nitride is formed during volcanic eruptions under high temperatures and pressure. The hardest stone If successful, wurtzite boron nitride may become the more useful of the two due to its resistance to oxygen at higher temperatures than diamond. This makes it ideal for use on the ends of cutting and drilling tools operating at very high temperatures, or as corrosion-resistant films on the surfaces of spacecraft, for example. Paradoxically, wurtzite boron nitride owes its hardness to the flexibility of the bonds between the atoms that form it. When the material is stressed, some bonds change direction by almost &09ordm; to relieve stress. After diamond and wurtzite boron nitride were subjected to the same process, something in the structure of wurtzite boron nitride made it nearly 80% harder, says study co-author Changfeng Chen of the University of Nevada, Las Vegas. Scientists emphasize that in order to prove the theory, single crystals of each material are needed. There is currently no way to isolate or grow such crystals. Today there is no unified classification of semi-precious stones. there is only a conditional division. Diamond is a mineral that is outstanding in every way. Like an unsightly doll (a nugget diamond really does not look like anything special in appearance), after cutting it turns into a delightful butterfly – a diamond worth hundreds, thousands and even millions of dollars. But it’s not only the unearthly radiance and fantastic price that makes this stone stand out among its peers. Diamond is the hardest of all minerals, which determines the widest scope of its application. Not every diamond can turn into a diamond – only the purest and largest stones deserve this honor. But even a small and cloudy nugget will not be thrown away as unnecessary, but will find application in the watch or nuclear industry, quantum computers or microelectronics, and, at worst, in the production of abrasive, drilling and cutting equipment. It’s Diamond!

General information about diamonds

Do you know the formula of diamond? Even a preschooler who has no idea about chemistry can remember it. It’s just C, which means diamonds are pure carbon (ideally, of course). What had to happen for carbon to turn into diamond? Many hypotheses have been put forward on this matter. The most convincing of them claims that diamonds are formed at very great depths (over 200 km) and under tremendous pressure – there carbon forms a special cubic lattice inherent in diamonds. During volcanic processes, carbon crystals are carried closer to the surface, where they are discovered by diamond miners. This process is very slow: the age of diamonds is measured in hundreds of millions, or even billions of years. So when, during intensive mining, diamond-bearing kimberlite pipes and other rocks are depleted, the reserves of this stone will dry up for a very long time.

According to scientific data, some diamonds are of extraterrestrial origin. They came to us with meteorites or came to us as a result of a supernova explosion. It is assumed that some of them are much older than the solar system!

• unsurpassed hardness – 10 on the Mohs scale;
• the highest thermal conductivity among solids – 900–2300 W/(m K);
• vanishingly low coefficient of friction on metal (in air);
• refractoriness and resistance to high temperatures;
• resistance to most aggressive acids and alkalis;
• high refractive index of rays combined with transparency;
• the ability to luminesce (glow) in x-rays and ultraviolet light.

Diamonds are not only white, but also colored. Brown and yellow colors reduce the cost of a diamond, blue, blue, pink, red, green – increase it to sky-high heights.

The main characteristic that decides the fate of a rough diamond is transparency (“clear water”). That is why black diamonds (carbonados) have long been considered exclusively technical. However, occasionally you come across evenly colored black diamonds that retain some transparency and characteristic shine. They are mind-bogglingly expensive.

How is the hardness of a diamond measured?

Even a child knows that the strength of a diamond is incredible (meaning its hardness, not its resistance to shock). It is taken as the basic value on all measurement scales. And this is surprising, because diamond’s closest relatives, graphite and coal, which have the same elementary chemical composition, cannot boast of outstanding strength.

The secret of diamond hardness lies in the unique conditions of its formation: high temperatures and incredible pressure. With them, carbon atoms form a unique cubic crystal lattice. This determines the incredible hardness of the final substance, which can exist in natural conditions for billions of years!

Unsurpassed hardness allows diamond to be used in the production of equipment for drilling and ultra-precise cutting. No substance can resist the standard!

Mohs scale

The first successful attempt to create a scale of hardness of materials belongs to the German mineralogist Friedrich Mohs. Despite the fact that this system was presented to the scientific community back in 1811, it continues to be used to this day, mainly in application to minerals of natural origin (including precious stones).

The hardness of a diamond on the Mohs scale is 10, that is, this mineral was taken as an absolute: a priori there is nothing harder than it. The basis of this test is scratching. If a scratch remains on the surface of the test sample, then it is a priori softer than the standard.

The second place in hardness on the classical Mohs scale is held by corundum, which includes sapphires and rubies – 9 points. You can only scratch them with a diamond!

However, the very rare natural moissanite and its artificial analog carborundum (chemical formula SiC) have a strength of as much as 9,5 Mohs points. By the way, carborundum often replaces diamond both in industry and in the production of jewelry. Visually, it is practically indistinguishable from its noble brother, but costs an order of magnitude cheaper!

Everyone knows that diamond has greater strength than graphite, despite the identical chemical composition. However, not everyone knows that they are at diametrically opposite ends of the Mohs scale. The hardness of graphite is comparable to that of talc, and this is only one!

Rockwell system

With the advent of synthetic materials and super-hard alloys, the generally accepted Mohs scale has become inconvenient. Many systems were proposed, but in the metallurgical industry the Rockwell scale (more precisely, the Rockwells, because there were two of them, distant relatives with the same surname) took root most of all.

The Rockwell hardness of diamond is not measured – it is taken as a standard and the main working tool. The Rockwell measuring machine visually resembles a sewing machine, but instead of a needle, a diamond cone is used, and fabric replaces the material being tested.

The sample is exposed to a diamond cone with a given pressure for several seconds, then the parameters of the dent are assessed on a letter-numeric scale.

What’s harder than diamond?

Many attempts have been made to create or find in nature a material stronger than diamond. So far they have not been successful: obsidan, titanium, super-hard alloys, all kinds of innovative materials cannot compete with the noble standard. Moreover: many chemists and physicists even argue that substances stronger than diamond (more precisely, harder) cannot exist.

The most famous and scandalous story involves a substance called lonsdaleite, which in a chemical and physical sense is a hexagonal diamond. In the 60s of the last century, this mineral was synthesized artificially, and a little later it was discovered in small quantities in meteorite craters.

In 2009, a group of Chinese scientists published a sensational paper claiming that lonsdaleite is more than half as hard as cubic diamond (as we know it). Unfortunately, these data turned out to be a hoax and were not confirmed even by the calculations in the above work.

The most successful attempt to create a substance harder than diamond was made quite recently, in 2021. A duo of American scientists managed to produce hexagonal diamonds from graphite using targeted explosions. The resulting samples demonstrated better sound conductivity than classic cubic diamond, which theoretically indicates greater hardness.

Unfortunately, it has not yet been possible to test the theoretical calculations of American scientists experimentally. And the disgraced lonsdaleite, obtained from graphite by exposure to colossal pressure, shows a strength of only 7-8 points on the Mohs scale. And it’s unlikely to be used: it consists of crystals visible only under a microscope, and obtaining this substance is fantastically expensive.

There are other substances that are not much inferior to diamond in hardness: fullerites, all kinds of boron compounds, carbyne, and so on. They are slightly softer than diamond, but often surpass it in other characteristics: strength, resistance to chemical attack and ultra-high temperatures.

A stronger substance can be created from cubic diamond (for example, using nanoengineering). The Japanese succeeded, but how to process this unprecedentedly hard material?

Can a diamond be scratched or broken with a hammer?

Based on the above, we can conclude: it is impossible to scratch a diamond. This makes it possible to quickly identify rough glass counterfeits that are easily scratched by a steel needle or nail file. True, imitation diamonds like cubic zirconia, and even more so carborundum, cannot be recognized in this way.

But there are plenty of substances stronger than diamond – and even steel! This means breaking a diamond is quite possible. Naturally, the stone will calmly survive a fall from a considerable height, and even if you step on it, nothing critical will happen. But if you hit the diamond with force with a hammer, it will crack, otherwise it will crumble into small crumbs.

But you shouldn’t do this: the experiment will be too expensive, and the world will lose another diamond that has been formed over hundreds of millions of years!