Gold - a report on the mineral, its properties and production

Gold is an ancient, one of the rarest, noble yellow metal that people began to mine in the Neolithic era. Humanity began to use gold even before our era. But if now our first association with gold is luxury and jewelry, then before this was far from the case. First of all, gold was used as a tool for hunting animals. Spear tips were made from it.

Nowadays, gold is one of the main metals used in jewelry.

Physical and chemical properties of gold

Gold itself is a very soft metal by nature. It is very easy to scratch, and to avoid this, stronger metals are added to the composition at the time of jewelry production. For example, silver, copper or platinum. But the melting point of gold is more than a thousand degrees. This metal is also very ductile, which allows it to be forged into sheets with a thickness of only ~0.1 microns. This is called gold leaf. It also conducts heat well and is often used in cables.

Gold comes in different colors: just yellow, yellow with red shades, lemon yellow, white, pink, green and even blue. It depends on the composition of the metal. If you mix gold, silver and copper, you get yellow color. With more copper, the alloy will give a red tint. And if you add more silver, the mixture will turn lemon-colored.

"Golden" story

This story begins in ancient times, because it was this material that gave rise to a new era - the era of metals. People then praised it for its unusual “sunny” color. It was believed that only people of noble blood could possess this metal. This was prestigious, because gold has always played an important material role. It could be exchanged for anything, and women decorated their hair and clothes with it. In addition to the pros, there were also cons. Gold is wealth, and wealth often led to unrest and war. The desire for independence was stronger than humanity, and people died. A lot of people.

Why is gold difficult to mine?

Illustration of gold mining by washing gold-bearing sand
Gold is a metal that, unfortunately, is almost impossible to extract, even if there is a considerable amount of it in the bowels of the earth. The difficulty of finding it is that it is scattered throughout the mine or the ocean floor. But at the same time it became the first metal that man found. Almost all gold is found in the metallic core of the earth, where it is extremely difficult to obtain. But nothing stands still, technology is improving, and over the past few years people have begun to mine many times more of this metal. It has been found in small rivers and even streams.

Abstract on the topic: Gold is a mineral

We have prepared several short messages about such a mineral as gold. Find out when this precious metal first began to be mentioned, its properties and where it is mined. Use the material to prepare school essays and reports.

Message 1

Gold is a fairly noble and beautiful metal, yellow in color. It attracts many with its brilliance and grace. For us common people, we know gold for its beautiful jewelry. Many gold rings, chains and brooches were created by craftsmen using this metal. It turns out that gold has been known to people since ancient times. Mentions of it can be found even in a book such as the Bible. Weapons were decorated with gold, expensive jewelry was made for women, gold bars were given as gifts and, of course, coins were made from it.

If we consider gold in its pure form, then this material will be quite soft. It is quickly damaged, almost from a touch. Therefore, experts, in order to make gold products stronger, decided to add platinum, copper and silver to it. Gold and its properties have always interested people. When experts began to study the material in more detail, they noticed that gold conducts well, not only heat, but also electricity. Gold cannot oxidize; it can only be dissolved if you use a solution of sodium or potassium cyanide. Gold began to be classified by color. Each of its colors always depends on the other metals added to the composition of gold. We are used to thinking that ordinary jewelry contains gold, but this is not true. Almost all gold jewelry consists directly of this metal, plus an alloy of copper and silver. If the alloy is like this, then the color of the decoration will be yellow. If you add a little more copper to gold, then all products made from it will have a reddish tint. People know white gold, lemon yellow gold, blue gold and even green gold. And every time people add other metals to the main composition of gold.

Of course, gold is one of the most ancient metals. Its mining began when people discovered copper deposits. Gold has always been a very rare material, so it was valued and even fought for its deposits. At one time there was even a gold rush that covered vast territories. People were chasing gold, each trying to find more than others. It is believed that the largest gold deposits are located in South Africa, China, Peru, Australia and the USA. Russia also has some gold reserves, which are located in the Amur region, Chukotka and the Krasnoyarsk Territory. Gold mining methods have always depended on the types of gold deposits.

If gold had many impurities, they tried to extract it using regeneration. Mining for nuggets has always entailed the use of a panning method. Mining for gold has always been a painstaking and time-consuming job, but many people enjoyed it and it was a great way to get rich for a long time. It is believed that today almost the entire world's gold supply is stored in the form of gold bars in banks, the rest is represented in jewelry and some precious items. People have learned to use gold in many areas and areas of life. Gold is well used in industrial and economic fields. It is widely used in medicine, cosmetology and even in the manufacture of glass for aircraft and ships. Still, we are accustomed to thinking that gold is beautiful jewelry on display in jewelry stores, the purchase of which brings joy to many people.

Message 2

Gold is one of the few precious metals. Humanity has been using gold since long before our era. But it was not used as an element of luxury. Ancient people used gold as a weapon. They used gold to hunt animals. Tips for spears and arrows were mainly made from gold because metal was difficult to find.

Now gold is more often used as an element of luxury. A lot of different jewelry, rings, earrings and many other types of jewelry are made from gold.

Despite the fact that gold is one of the softest metals, its melting point exceeds a thousand degrees. While other harder metals have a melting point that is two times lower. Gold is also a very good electrical and thermal conductor. Despite this, for some reason, gold is not used as a radiator. But they are very widely used in cables.

Gold also has a fairly high ductility. To explain with an example, from one ounce of gold you can get as much as 80 kilometers of gold thread less than a human hair thick. By the way, very high-quality and durable threads are obtained from gold threads.

Gold is a metal that is extremely difficult to mine. But this does not mean that there is little of it on our planet. There is an assumption that there is gold even in the atmosphere, but it is invisible to our eyes. Gold is the first metal to be discovered by man. The main concentration of gold is in the metallic core of the earth. That's why it's so hard to get. Over the past five years, humanity has made a huge leap in gold mining. Gold is also mined in various streams and rivers. This is how the largest nugget was found, weighing 72 kilograms. He was only five centimeters underground.

The largest gold mining continues to this day in the Republic of South Africa. More than five hundred tons of gold can be mined in South Africa per year. But this is not so easy to do. To bring this gold to the surface, seven hundred tons of other rocks have to be crushed. Tons of water are used to wash the gold ore. A large amount of fuel and various chemicals are wasted. This gold is mined in a mine three and a half kilometers deep.

Now an ordinary person can easily purchase any gold jewelry for a fairly large sum. After all, gold is so difficult and expensive to mine. But what can you not do for such beauty?

Message 3

Gold is a precious metal with a distinct golden color and shimmer. In the periodic table it ranks 79th. People started looking for gold many years ago. This metal, without any impurities, is very soft and elastic, because of this it can easily change its shape. To make it stronger, copper, silver, and platinum are added.

This metal has a high density and is easy to mine. It is very heavy on its own. Plastic, perfectly conducts electricity and heat. Gold can withstand everything; it does not oxidize. It can only dissolve in a solution of Na or K. Gold can be identified by color, the color depends on what is added there. If you look at gold without impurities, then it is a bright sand color, but if it has a tint of red, then there is a lot of copper present. If the gold is bright yellow with a lemon-colored tint, then there is clearly a lot of silver present there. It can also be light silver in color if platinum, nickel, or palladium is added.

Gold also comes in green, black, blue, and purple. Each gold has its own hallmark, it depends on the ligature. Gold has its own research and assay scale. It is the rarest metal. It began to be mined a long time ago at the same time as copper. Scientists suggest that over the course of their entire life on earth, people have mined 165 tons of gold. If you pour all this gold into one ingot, you will see a cube 20 meters wide. The best gold deposits are in China, Australia, the USA and South Africa. But there are also such places in Russia: Chukotka, Krasnoyarsk Territory, and Amur Region.

There are different methods for mining gold. Which method will be used depends on the type of deposits. To obtain a nugget, the washing method is used. Where dispersed gold is used, the method of dissolution in mercury is used. If the ore contains gold, there is a huge content of impurities, then it is mined by regeneration. But at the same time they use high technology. Statistics show that 90% of the gold that is mined is stored in a bank, or with individuals in the form of all kinds of jewelry. The remaining 10% is used in industry.

Mining for gold is very hard work. After all, there is very little of it. And for a huge piece of land, very little gold can be mined there. Suppose there is a large amount of this metal in the ocean, but it is almost impossible to find it, because it is scattered along the bottom. It's the same on land. But of course there are also rich deposits. This is one type of metal that has conquered the planet and become noble and number one on earth.

Message 4

Gold is not only an element of the periodic table. It is also a very beautiful and quite mysterious metal of noble yellow color. It has both material and historical value.

Story

Properties of gold

Gold, despite its elegance and beauty, is a very heavy metal. It is not exposed to virtually any chemical influences, which is why it has earned the title “noble metal”. It is very soft and ductile, so the number of different types of gold products is constantly growing, but its excessive fragility does not allow it to be used in its pure form - only with the addition of silver or copper. By the way, their color directly depends on the percentage of these materials in the product. Good thermal conductivity also allows the use of gold in the manufacture of various types of devices.

Production

Mining gold is not an easy task, because despite the fact that it is the most popular metal, it is also low-concentrated. That is, there is a negligible amount of it in a large space. For example, there is a lot of this rock in the World Ocean, but it is so widely scattered across the ocean floor that it is almost impossible to get it. The same applies to the earth's crust. But there are also rich deposits. The main thing is to know where to look. The types of gold mined also directly depend on the location of mining. In the ground, the pieces of gold are crystal-shaped, and those closer to the water are round.

At all times, gold mining has been a very profitable business, but in reality there is not so much of it.

This metal, which conquered the earth and became one of the most important metals, will never lose its value. People have tamed it. We learned to mix and change, make beautiful things and exchange them for useful ones. It will always remain metal rich and noble.

Message 5

Gold is the only metal that, in its pure form, has a beautiful bright yellow color. It has a good shine, which increases when polished. Density - 19.3 g/cm3, melting point - 1063°C, Brinell hardness - 20, color - yellow.

The average gold content in the lithosphere is 4.3 x 10-7% by mass.

People have been mining gold since time immemorial. There are several main methods for extracting gold, the main ones being washing river sand and extracting gold-bearing rock in mines. Gold can be extracted from gold-bearing rock by amalgamation, chlorination, or cyanide.

In total, more than 140 thousand tons of gold have been mined by humanity. Of this, more than 40% went to jewelry, and 12% to technical purposes.

Collected in one place, gold mined throughout history would form a cube with an edge equal to 19 m, that is, the height of a five-story building (while the ore and sand from which this gold was extracted would represent a mountain more than 2.5 km high). The gold currently mined throughout the world in one year would fit in a medium-sized room.

There are primary deposits of gold, placers into which it falls as a result of the destruction of ore deposits, and deposits with complex ores in which gold is extracted as an associated component.

Major gold mining countries: South Africa, USA, Australia, Canada, China and Russia.

In Russia, Erofey Markov is considered the first gold miner, a monument to whom stands in the city of Berezovsky near Yekaterinburg.

Natural or native gold, as a rule, is not pure and its purity ranges from 500 to 950. The main impurities in native gold are silver and copper, as well as many other elements, therefore, to achieve high purity, it is subjected to refining (purification) at special enterprises.

Refined gold is produced in bars of various weights - 1 gram, 5 grams, 10 grams, 50 grams, 100 grams, 500 grams, 1,000 grams, 12,000 grams, or in the form of gold coins weighing from 1/2 gram to 5, 10 and even 100 kg, as well as in the form of tapes, strips, foil, wire and other semi-finished products.

The gold content in bars and gold coins is about 99.99%, the remaining hundredths and thousandths of a percent are impurities (lead, iron, antimony, bismuth, copper or silver, etc.). The amount of impurities is regulated by GOST.

Gold is a very ductile and soft metal; it can be rolled into sheets up to 0.0001 mm thick. (“leaf” gold), and from one gram draw a wire 3.5 km long.

Gold does not oxidize in air and is resistant to moisture, insensitive to acids, alkalis and salts. The exceptions are a mixture of hydrochloric and nitric acids in a ratio of 3/1 (regia vodka), sulfuric acid in combination with manganese or nitric acid, as well as hot selenic acid, in which gold dissolves quite easily.

When combined with mercury, gold forms an amalgam (once this property of gold was used for “hot” gilding of jewelry: the jewelry was rubbed with amalgam and heated over hot charcoal; when heated, the mercury evaporated, and a thin layer of pure gold remained on the product).

In the jewelry industry, pure gold is used to form alloys of precious metals. Gold alloys are ideal materials for making jewelry. Unlike too soft pure gold, they are more durable and wear-resistant, and when adding various alloys, they easily change color to white (white gold), red, green, pink, etc.

Where is gold mined?

Most gold mining is now done in the Republic of South Africa. In one year, experts can find more than five hundred tons of gold. For such a cosmic result, they have to dig through more than seven hundred tons of other various rocks. It also takes an incredible amount of water to wash the gold ore.

Gold mining is also carried out in China, the USA, Australia and Peru. Russia also has gold metal, but not so much. Chukotka, Krasnoyarsk Territory and Amur Region are specialized for its extraction.

What have we learned?

Gold is a valuable metal and is widely used. The article briefly describes the characteristics of the metal and its location in nature. Gold is used in jewelry, industry, dentistry, in the production of medicines, and in the treatment of cancer, which can be discussed in a report or essay on the topic “Gold. Properties and Application" for 4th grade.

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Gold mining methods

There are several different ways to mine gold. Which method will be used depends on the type of deposit. Nuggets are obtained very simply - by washing. Using this method, a nugget was found that is considered one of the largest. His weight was 72 kilograms. And they found it only at a depth of five centimeters. Scattered gold is mined by dissolving in mercury. The regeneration method is used when the ore that contains gold contains a huge amount of other impurities. But this is a very difficult method that requires the introduction of high technology.

Gold for medicinal purposes

The first methods of treatment with yellow metal, as well as its basic physical and chemical properties, were reflected in the works of ancient scientists and alchemists. Gold was studied during the Middle Ages, and scientific research in this area continues today. Scientists from different countries are striving to find new ways to use the precious metal in medicine and industry.

Even in ancient times, gold was considered a remedy for many diseases, a real elixir of life. Our ancestors believed that if gold has power over a person, then it can cure his ailments: remove pain, give strength and vigor, relieve stress, eliminate emerging symptoms of diseases.

The healing properties of gold include:

Relieving inflammation;
Improving metabolic processes in the body;
Allergy cure;
Beneficial effects on the nervous system;
Stimulates brain activity and improves memory;
Increasing the endurance of the human body.

When treating with gold, you do not need to do any special procedures; it is enough to wear jewelry made from this precious metal. Ancient healers believed that gold prolongs life.

The main medicinal properties of gold are usually used in alternative medicine. Gold jewelry is recommended for anyone who has heart problems, liver problems, skin diseases, or women's problems. The precious metal is capable of killing viruses and harmful microbes, so it can serve as an additional means of prevention during the flu season.

The beneficial properties of the solar metal allow folk healers to recommend wearing gold for:

Energy replenishment of the body;
Gaining self-confidence;
Protection from the evil eye and damage;
Maintaining a good mood and quickly recuperating;
Successful fight against depression and stress;
Productive brain and memory function.

The use of gold for medicinal purposes may not be suitable for everyone: some people have an individual reaction to the metal.

Those who like to wear a lot of massive jewelry made of yellow metal need to evaluate whether they are harmful to the body. The properties of gold, aimed at helping a person, may not be useful at all in some cases. If you have sensitivity to metal, hair growth may worsen, depression may appear or simply a bad mood may prevail, tooth decay may begin, malfunctions in the functioning of internal organs or simply an allergy to the skin may occur. In such situations, the use of gold jewelry must be strictly limited.

Where is the mined gold located?

Gold reserve storage

According to statistics, almost all the gold found, specifically 90%, is in the bank. It can also be kept by private individuals under the guise of jewelry. Only 10% of all mined metal remains for industry.

In the world list in terms of the volume of gold held in state reserves, the leader is the United States. As of 2022, the US gold reserve is more than 8.1 thousand tons. Russia, with gold reserves of about 2.3 thousand tons, is in 5th place in this ranking.

Plasticity and malleability

Since ancient times, various products have been made from gold - statues, dishes, jewelry. The ability to be used in various fields was ensured by its high malleability. Thus, in the absence of heating, the metal can be forged into translucent sheets. The minimum thickness of such a sheet is 0.1 micrometer. Compare: the thickness of a human hair is 80 micrometers. With all this, gold retains both its properties and its color. This form of metal production is called “leaf”. Today, gold leaf is used to cover interior parts, domes of temples and cathedrals. From one gram of metal you can make a sheet with an area of up to 0.5 square meters. Minimal consumption and, accordingly, low cost makes it possible to decorate various materials with gold. Moreover, thin wires for microcircuits are made from it.

Metal mining from ancient times to the present day

Gold is an amazing metal. All minerals are mined to be used and consumed, but they are mostly hoarded. States and individual citizens.

From Egypt to America

It is believed that the Egyptians were the first to mine the yellow metal. Chronicles recorded metal mining in the Arabian-Nubian province. There were rich deposits there. Even in the time of Thutmose III, about 50 tons of gold were mined there per year. And in total, during its operation, the deposit produced more than 3,500 tons of metal.

However, the deposit has become depleted. Many historians associate the decline of Egypt precisely with the fall in the amount of precious metal in the state.

New deposits have been found in Europe (Spain, Austria-Hungary). And with the Spanish conquests in America, solar metal poured into the Old World in a torrent.

Over the entire history of mankind, about 167,000 tons of the precious metal have been mined.

Of these, 12% were used in industry, and of 50% people made jewelry.

In any case, the extraction of precious metals stimulated the development of metallurgy, and at the same time international trade.

Modern gold mining

The days of the gold rush that shook countries are long gone. Cruel romance, when thousands of people went bankrupt and many died, is a thing of the past. Although only a few of them became obscenely rich.

Now gold mining takes into account profits and overhead costs, and does not take a step without preliminary exploration of deposits, assessment of economic risks, and construction of mines using the proper equipment.

In modern times, gold ore is mined mainly at great depths or from depleted placer deposits. Gold in nature is not a renewable resource, but it has been mined since time immemorial. Even in the old days, the cream was skimmed from the richest deposits, and we, descendants, are left with the hard work of choosing gold from already “refined” places. Or, as an option, the yellow metal is mined at great depths.

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Great sayings about gold

Gold as a mineral

Gold has always been revered and praised in literature, art and politics. They talked about its moral shades. They valued beauty comparable to a deity. Here are the sayings of great people who have gone down in history.

«Gold is tested with fire, a woman with gold, and a man with a woman.».

Roman philosopher, Lucius Annaeus Seneca.

«There will always be gold, gold will be money when the dollar, euro, yuan and others will be just memories.»

American politician, Richard Russell.

“Dare to love yourself as if you were a rainbow with gold at both ends.”

– Aberjani Schiff.

«Man tests the hallmark of gold, and gold tests the hallmark of man.»

English historian and preacher, Thomas Fuller.

Think about it, perhaps gold will become the source of your inspiration and give the world new talents.

Varieties and characteristics

A fossil such as pure gold has extraordinary softness. Because of this, the material is very easy to damage, even if you run your fingernail over it, it can get scratched. In order to give the metal strength and reliability, certain alloys are created with the addition of silver, platinum and other elements that make the compound harder.

Due to its high level of density, this mineral is very easy to extract from land and water bodies. If we compare in terms of heaviness, this precious metal takes an honorable 6th place, inferior to the following elements:

Platinum;
Osmium;
Iridium;
Rhenium;
Plutonium.

Excellent ductility can also be highlighted. It is possible to make gold sheets that are only a few millimeters thick. This element has proven itself well as a conductor that conducts electricity and heat without difficulty. Under normal conditions, this material is not affected by acids, and as a result does not oxidize.

Gold jewelry

Every Hollywood movie girl's dream is a gold ring with a large diamond.

But let's still look at other options. To expand the range of gifts for loved ones.

A gold bracelet is a beautiful and light decoration for your hand. Will highlight the elegance of any lady.
A brooch is a piece of jewelry that will show your individuality and inner world. It can be based on floristry or animals. The best addition to a business suit.
A tiara is a small, half-open crown. Used in very rare cases - a wedding or the Miss World competition.
A tie clip is a men's version of jewelry. It will always show the status and authority of its owner.
Cufflinks are also a men's decoration for shirt cuffs.
A necklace is a whole composition of precious stones. Which are connected by gold or silver chains.
Ring. Everyone is definitely familiar with him. A sea of varieties. From the most complex configurations to stylish classics.
A necklace is a woman's neck decoration. Usually straight, without complex connections.
Earrings need no introduction. A universal gift for any girl.

Distribution in the surrounding world

Gold can be found mainly in the form of nuggets. Trace amounts are found everywhere, but large deposits are found only in a few places. It can be found either in pure gold deposits or in combination with other related metals. Ore or vein gold is located in primary deposits, and wash or placer gold is located in secondary deposits. Vein deposits, depending on how deep they are from the surface of the earth, are divided into high-temperature and low-temperature. The presence of silver or copper in the rock gives it a different shade: from golden yellow to silvery white. The admixture of copper gives it a pinkish tone with a metallic sheen.

The world's oceans contain gold in the amount of 5–10 mg per 1 ton of water, so it is unprofitable to extract it from sea water industrially. Gold is found both in the form of nuggets and as part of ores. In addition, it is found in the form of compounds with hydrogen sulfide, which occur in geothermal waters. Metal is obtained in several ways:

leaching from gold-bearing rock;
amalgam method;
cyanide method.

The level of purity of gold and the presence of excess impurities in it is indicated by a sample. It is written in ppm (%o) and shows the percentage of pure gold. So, 560 sample means that the sample contains 560% and 440% foreign impurities.

The most "metallic" metal

Gold contains all the most obvious properties, which scientists call metallic. In terms of electrical conductivity, it is second only to silver, copper and pure palladium. In terms of thermal conductivity - the same as silver, copper and cobalt. In its ability to absorb thermal energy, gold is second only to exotic bismuth, ahead of mercury and silver. In terms of other “metallic” properties - malleability and light reflection - it is a champion. Gold is the most ductile metal in the world, and its shine is a legendary concept.

The molecular structure of gold is also very “metallic”. It is a geometrically regular crystal lattice with positive ions at the nodes and a dense gas cone between them. This part of the atom consists of free electrons located at the outer energy level. They create an attractive force between the lattice nodes, which ensures the ability of the metal to deform without violating its overall integrity. This is how the most ductile metal works.

Assays - Gold marking

On rings, for example, they always tie a string with a small metal piece. There are numbers written on it. This is a sample of the precious metal. Fineness is the gold content of a given item. Russia has its own sample determination system.

Let's look at some samples of gold:

№ 375: Gold content without impurities - 30%. 70% is occupied by various alloys (copper, silver, etc.). The most inexpensive jewelry is made from this sample. They turn black quickly, but can be polished.

№500: Gold content without impurities - 50%. The other half is additional materials (silver, copper, lead, iron). On the jewelry market, the price varies from 8,000 to 15,000 rubles.

№585: One of the most popular samples in the country. Gold content - 59%. Additional elements are the same as in the previous ones. But experts believe that it is better to purchase 585.

№750: The percentage of pure gold is 75%. A distinctive feature is its bright shine and variety of colors. The price of such jewelry starts from 65,000 rubles.

№999,9: the purest gold, without impurities or additives. This is considered investment gold. Jewelry is not made from it, as it is a very soft metal.

Plasticity test

The ductility characteristics of metals are usually determined by static tests. The most revealing is the tensile test. To find out which metal is the most ductile, it is necessary to subject samples of the same size to this effect under similar temperature conditions. The amount of deformation that a metal sample can withstand before failure is an objective indicator of ductility.

The numerical expression of the tensile test result is two main coefficients. Relative elongation is the percentage ratio of the increased length of the sample after rupture caused by deformation to the original one. The most ductile metal - gold - has an indicator of 65%. For comparison: for iron – 40-50, for aluminum – 30-40.

The second indicator of plasticity is the relative narrowing of the cross section of the sample. For gold, the initial cross-section of the sample is 90% larger than what it had before breaking. For aluminum this figure is 80%, for copper – 75%.

How to distinguish gold from fake

The inertness of gold distinguishes it favorably from other metals. This noble metal is easy to distinguish from other outwardly similar alloys by a number of characteristics.

It has completely no magnetic properties. Real gold is not attracted to a magnet, but there are many base metals that have the same property.

An alloy containing gold will not react with chemicals. When iodine is applied to the surface of gold jewelry, there is no interaction between the metals.

When it falls, a specific sound is made. Comparing the sound of falling can help distinguish costume jewelry from real gold jewelry. A special feature of gold is its weight. A gold item has a lot of weight compared to jewelry.