About some characteristics of gold-bearing quartz veins. Features of searching for placers What does a gold vein in the rock look like?

Mining gold from stone involves a completed technological process of extracting the precious metal from the ore of primary deposits. The development of placers involves the use of the material flotation method with subsequent purification from impurities. Ore and placer gold sometimes forms nuggets.

Forms of finding gold

What does gold look like in nature and where is it found naturally? The noble metal is found in rocks and sea water in different concentrations and volumes. Some plants (for example, corn) are capable of accumulating small amounts of a component from the soil.

In what forms does the precious chemical element occur? Industrial concentrations of the precious metal are associated with primary and placer deposits. For each type of deposit, there are development technologies associated with the characteristics of the deposits.

There may be other chemical elements near the noble solar metal. The well-known natural alloy of silver and gold - electrum - is a combination of two precious metals containing noble components in equal proportions.

Sometimes the yellow chemical element forms nuggets. Depending on the conditions and location, they take on special forms. Ore gold is a rock material of quartz veins formed by hydrothermal processes.

The famous Holterman Slab, discovered in Australia, is a fragment of a quartz vein with a high gold content. In history, there have been discoveries of native metal in secondary deposits, differing in external parameters and appearance.

Methods for extracting precious metals

The extraction of the precious component is carried out by washing the deposited loose material with water. The high density of gold ensures its sedimentation in special installations.

Washing of the rock, depending on the volume of raw materials, is carried out using various devices and devices. Industrial development is carried out by dredges, which are a complex mechanized multifunctional unit operating on the principle of a multi-bucket excavator.

It is also used for underwater mining of precious metal placers with subsequent placement of waste material in dumps. There are dredges that operate on the principle of a vacuum cleaner.

They are designed for great depths and are intended for sucking and pumping rock with subsequent enrichment (increasing the concentration per weight unit) of raw materials in factories.

Washing of loose material containing gold can be done in trays. They are designed for artisanal extraction of precious components and are the main device for exploration work.

Trays come in different designs and are made from different materials (wood, metal, plastic). Unprocessed spot gold is subjected to purification from impurities of minor materials and metals. As a result, metal of the highest standard is extracted from black concentrate.

The development of primary deposits and the extraction of a noble chemical element from rocks that contain the precious component involves a certain set of technological and production aspects related to the search and development of raw material reserves.

Extraction of precious metal from primary deposits

Gold-bearing quartz veins are formed in rock cracks under the influence of hydrothermal brines. Their distinctive feature is the color of the silicate compound, in which the noble chemical element is in a finely dispersed (in the form of small particles) state.

Gold in a stone can be contained in the form of grains. In order not to confuse the noble metal with pyrite (a compound of sulfur and iron), you need to determine the color of the metal feature. Gold on the sampler (biscuit) leaves a yellow streak.

If there is gold in the rock, then under mechanical stress it will behave like a metal with malleability and the ability to deform under the influence of weight.

To determine the presence of a noble metal invisible to visual detection in a rock, it is necessary to subject the ore sample to chemical treatment. However, not all methods are suitable for identifying the presence of gold in rocks.

The property of a noble metal to form an amalgam with mercury is not the safest way to separate gold from a stone. Dissolving crushed ore material with subsequent processing in aqua regia is not at all environmentally friendly.

Iodine (solution or crystalline) when interacting with a metal forms a compound. The solution to be determined for the presence of a noble metal is thoroughly mixed and filter paper is periodically dipped into the substance. After drying, it is burned.

If the stones contain gold, the ash remaining after manipulation becomes purple. To extract fine gold from stone, you can use crystalline iodine. Working with it is practically safe.

To extract visible gold from a stone, you can wash the crushed ore. This method is called gravity, it is used in the development of placer metals.

How to obtain gold from stones on an industrial scale? The technology for developing primary deposits involves a combination of various methods. The crushed ore is treated with chemical compounds. Obtaining a pure precious component involves purifying raw materials from impurities of other metals using electrochemical and chemical methods.

Which methods to use in practice depends on the nature of the primary raw material and the methods of its extraction from the rocks. It is more profitable to extract gold from secondary deposits. Material that has been mechanically processed in water streams has the highest class of purity.

But the development of primary formations is associated with other forms of metal occurrence in nature, among which there may be “pockets” with crystalline formations of gold nuggets.

Gold is a noble metal, the mining of which began in ancient times. It may seem that this material is now of no practical value. But even in the modern world, you can see cases of brutal bloodshed that are directly related to this metal. This article will talk about where you can find gold and how you can do it.

A little history

If we go back to the times of Ancient Rus', it is reliably known that lands containing gold were not discovered at that time, even despite the fact that the territory of the state was quite vast. Ruler Ivan III was obsessed with the goal of finding the noble metal and even invited specialists from distant Italy for this purpose. But to his regret, only a small piece of gold was found, which was only enough to make a small cross.

The next seeker was Ivan the Terrible. For the sake of gold, he even conquered Siberia with the help of a huge army, but he never achieved the expected result. The same fate befell all the other rulers of Ancient Rus'. But the turning point in the history of gold mining was the coming to power of Peter I. It was under the power of this ruler that the first items of clothing and jewelry that contained gold and precious stones began to appear.

The first gold nugget was mined in 1945 by a Russian peasant from the Urals who was building a house on the river bank.

While digging a hole, he found golden grains of sand. The peasant immediately showed the find to his friend, who was also a silversmith. The master confirmed that the nugget was genuine. Experts arrived at the place where the grains of sand were found and began further searches. But unfortunately, they left with nothing. And only two years after the discovery of the deposit, a decision was made according to which it was necessary to continue the search and dig a mine. This decision turned out to be more than successful.

At the bottom of the dug shaft, a large amount of gold reserves were found, which marked the beginning of larger-scale mining of the metal.

Where to look

The question of how to quickly and efficiently find gold in the ground, as well as in what places this should be done, worries many seekers. In fact, there are many places where gold particles are present, but they are contained in very small quantities. If you are serious about searching for a large mine, then luck may turn your way, but the likelihood of this is negligible.

A small part of the precious metal can be found in sea water. According to experts, if you separate all the sea water from the gold reserves, you will get about 10,000,000,000 tons of metal. This figure is simply shocking. But at the moment there is not a single way in which this could be done.

It is pure precious metal that can rarely be found in nature. Most often, gold is found with many impurities, from which the metal will then have to be purified. The most common place where you can find pure gold without impurities in large quantities is in quartz beds.

Under the influence of natural elements, such as wind or rain, layers can be destroyed. As a result of this process, a solid piece of gold nugget is formed. Also, gold reserves can be deposited in several types:

• Eluvial deposits;
• Residual deposits;
• Bottom sediments;
• Terrace deposits.

Residual deposits can be observed directly near the vein itself, which has been subjected to physical or chemical influence. Eluvial deposits are most often located at the foot of mountains.

This is what quartz layers look like.

Terrace deposits are in most cases found at the bottom of the river. After a certain time, the river erodes the land, as a result of which an additional bottom is formed. The old bottom rises above ground level, which is why it is called a terrace.

The terraces, which are several hundred years old, contain a very large amount of gold reserves. Bottom sediments form at the bottom of rivers in the form of precipitation. With the help of rain, gold moves along the river bed.

Ore development.

Today, the process of mining gold deposits is not much different from the extraction of all other metals and ores. First, a deep shaft is made, and then huge pieces of ore are lifted to the surface, which contain what started all these searches and excavations. At the final stages, gold should be separated from all unnecessary elements and impurities. To do this, the metal is ground to a powder state.

Searching for gold in Russia

There is practically no exact answer to the question of how to find gold in Russia even today. The most promising regions for searching are the Urals, Chukotka, Magadan, and Amur. It was in these places that nuggets were discovered, weighing 16 kilograms. Similar finds are still in the memory of local residents.

But before you go looking for metal, you need to find out whether it is in a particular place. All the necessary information can be provided by geologists or indigenous inhabitants who are well versed in the given territory.

Very often, the discovery of gold deposits is mentioned in newspapers, so in order to collect as much information as possible, you should turn to archival data.

Industrial mining sites.

There are also special geological funds that collect information about gold mining in a particular region. Such funds can be of great help in advancing the search for a profitable mine.

If the places where gold reserves were found weighing 50 grams or more have become known, then nuggets several times heavier can be found there.

Based on everything that was said above, it should be concluded that before going to a specific region in order to start searching for precious metal there, you need to carefully check all the data, analyze the information, and view all photos and video materials.

How to search correctly

Finding gold is a very long process that can last for years. It is unlikely that in the first days of searching the digger will find something worthwhile. In order to somehow speed up this process and make it more productive, it is recommended to study a large amount of literature that can teach you how to properly organize your searches.

It has already been said that gold is found in quartz strata. To detect them, you need to pay attention to certain signs that are characteristic only of such deposits.

Gold dredge

After many years, the technologies used to mine gold in ancient times have not changed much. All that has changed is the work of mechanized machines instead of human labor.

Today, few people are engaged in gold mining using trays, since this method is no longer relevant and widespread. But the technology has survived. Today, many people use a huge machine that has a large number of trays.

A dredge is a device used to flush water from a river. It is this huge and noisy structure that is capable of extracting precious metal from river rock. Although this method is very effective and profitable, it has a very negative impact on the environment. After dredging, river beds are left in a deplorable state. But in order to know how to find and then safely extract gold from the river, it is recommended to use dredging as the easiest way to mine gold.

Gravitational differentiation

This gold mining technology involves grinding rock that contains the metal. After these rocks have been loaded onto trucks, they are taken to special mills. Inside these mills, huge stones crumble under the pressure of large balls made of strong cast iron.

After crushing, this entire mass is placed in a centrifuge, in which the earth and stones are separated from the pyrite. Pyrite contains particles of valuable metal. Very often the shine of the mineral is mistaken for real gold.

Modern mining technologies

Today, technological progress has made significant strides forward. With the help of the latest technologies, gold is extracted even from poor and almost deserted mines. Balanced deposits are also created.

In order to establish the use of heap leaching, it is enough to spend one year of work. In addition, it is a very profitable investment. In just a year, the mine owner will be able to hold entire ingots of precious metal in his hands.

Searching with a metal detector

There is an opinion that it makes no sense to continue gold mining in ore that has already been mined. After all, in order to find a few grams of metal, it is necessary to process a whole pile of rock, and this is a huge amount of work. The question arises: how to find gold, with the most accurate determination of its location?

On average, there are about five kilograms of pure gold per ton of land. If these data are correct, then metal mining becomes unprofitable. But there are certain places where quite a large amount of precious metal accumulates. Such places are called deposits. They are found by geologists who have relevant knowledge in this area. In such local accumulations, the gold coefficient is several times higher than usual.

In the deposits you can find nests and columns. These are places in which there is much more metal than in all others. The efficiency of mining can only be seen when the amount of precious material is calculated relative to the ton of rock that was processed. In order to learn how such calculations are made, you can study the corresponding video.

To find such deposits, a metal detector is used, which is widely used for such purposes. It significantly increases the level of efficiency and reduces the duration of search work. If the metal detector indicates something, then the sector must be carefully checked and, perhaps, even a soil sample must be taken and the rock washed.

Many years of practice have proven that gold nuggets are never far from each other. If one was found, then it makes sense to look further, since there should be more similar specimens nearby.

Metal detectors were first used about forty years ago in foreign countries. Today you can see instruments that have excellent sensitivity, which can indicate even a small piece of metal. The device shows exactly how you can quickly and accurately find gold in nature.

Scientists geologists tested dozens of instruments that searched for an identified object in a variety of conditions, both on land and in deep reservoirs. The test results proved that the metal detectors performed well and that they can conduct full-scale searches.

During the research conducted in the Irkutsk region, geologists managed to find more than a hundred nuggets, the total weight of which was more than 1 kilogram. Most often, such specimens are found on the surface of industrial dumps, and not on the surface of the earth, as is usually shown in movies.

There are different types of terrain that have unique prospects for mining, so searches should be carried out wherever possible. To avoid mistakes, there is a more proven and reliable option. Where gold can be found, mining must have already been carried out previously or continues to this day. Places where gold has never been mined do not present any prospects or opportunities for further exploration.

It is important to consider that excavations had already been carried out before your arrival. Therefore, if even highly qualified specialists could not find anything, then you are unlikely to be luckier than them. But there are also exceptions.

Geologists are interested in areas that have vast volumes. They do not pay attention to distant corners. Therefore, if you look hard enough, you can find small amounts of gold nuggets in those distant corners.

It is better not to skimp on buying a metal detector.

Small streams high in the mountains are another promising place where you can get metal. Light pebbles are carried away by the current, while heavier ones remain and accumulate at the bottom of the river.

Is it possible to find gold using a regular, amateur metal detector? Naturally, you can, but it’s better to use a tool that costs 30 thousand rubles or more, since it greatly simplifies the task.

Gold is found in minute amounts in almost all rocks that make up the earth's crust. It would seem that humanity should literally go crazy and try to extract this metal by any means. But, as it turned out, this is very expensive, and the costs of searching for it and extracting it from the rock will not be compensated by the amount of yellow substance obtained. To be convincing, we present the following fact: in one ton of rock you can find only 5-6 grams of the precious substance. The only good news is that in different types of ore its concentration may not be the same.

Often the precious metal is found precisely in quartz veins, where industrial deposits have been located for a long time. But even there, the amount of gold mined is much less than other useful metals located in the same place. Therefore, gold mining is considered a very labor-intensive process, which in complexity is second only to the extraction of expensive and rare platinum from ore.

Today there is a theory according to which there is several hundred times more gold in the earth's core. This is explained by the fact that iron-containing meteorites falling to the ground contain this metal in an amount equal to 5-6 grams per ton. Since the Earth’s core is also iron-containing, it is quite reasonable to assume that there are gold reserves there too.

Precious seas

An interesting fact is that this metal can be found not only in rock, but also in sea and ocean water. Moreover, in different seas and oceans its content is completely different, and the highest concentration is observed in coastal zones and areas with a hot climate. The world's oceans have the most yellow substance, followed by the Dead Sea. For reference, one ton of water in this sea contains 50 mg of this precious metal. By the way, man has already attempted to organize gold mining in the Dead Sea, but failed.

At the level of development of modern technologies, it is quite possible to extract gold from sea water, but doing so is not at all profitable. The fact is that a substance found in nature can be considered a mineral only if its concentration in one place is higher than the clarke value. But how much higher is a question of technology and the properties of the substance itself. At the moment, the level of gold content in sea water does not allow us to hope for obtaining millions of tons of the precious metal. But this is all a matter of time, since technology does not stand in one place.

Nature is designed in such a way that gold is found not only in water, but also in bottom silt. This fact was established by studying the bottom silt of the Red Sea. It turned out that it contains not only the precious metal itself, but also other useful and valuable minerals. Again, their concentration is negligibly small in order to organize large-scale gold mining. Therefore, scientists are looking for a way to process bottom silt, since it is much easier to get to than the earth’s core, for example.

Metal is brought to the sea by rivers, which wash away the rock along their route. Incredibly, the Amur alone brings more than 8 tons of precious metal per year to the Gulf of Tatar! Meteorites should not be overlooked, since they are dispersed into the earth's atmosphere annually in the amount of 3.5 tons, carrying with them 18 kg. gold, a large share of which comes from the World Ocean. But the active volcano Etna, which is located in Sicily, saturates the atmosphere with 2.5 kilograms of gold with each daily ash emission.

It's everywhere!

In fact, this substance is found not only in stone, sea or sand, but also in groundwater, animal bodies and even plants.

The French chemist Bertholet was the first to discover gold particles in the ashes of plants, after which he began to closely study this natural feature. It turns out that trees and bushes accumulate the precious substance in different ways. So, for example, from a ton of birch you can extract 0.5 mg. gold, while from a similar volume of spruce it was already 1.27 mg. The best “batteries” are considered to be corn and horsetail. And if gold is found in the ashes of plants, this can be considered a sign of its deposit.

If we explain the appearance of metal in plants quite simply, then the question of how it appears in the body of an animal remains open. For example, researchers at one of the British nature reserves discovered gold in the fur of deer. It is noteworthy that there is no trace of gold in the land and water located in the protected area.

Physical parameters and types of deposits

Gold is a very heavy metal, with a specific gravity of 19.3. It is unusually malleable and soft, although it looks very presentable, and therefore cannot be used in its original form. In nature there is only one type of gold isotope, the mass number of which is 197. The native metal that you see in the photo undergoes complex processing - refining, after which a chemically pure precious substance is obtained.

There is a distinction between placer and ore gold. The first option is found in quartz rocks or sulfide ores. But placers are a product of the destruction of primary deposits that accumulated in river valleys.

Primary gold deposits are associated with intrusive rocks: diorites, quartz diorites and granites. They are called intrusive or intruded because they were formed as a result of the solidification of magma that penetrated from the depths into the upper layers of the earth's crust, but did not reach the surface. Intrusive bodies formed by the solidification of magma that filled vertical or slightly inclined cracks in the earth's crust are called dikes.

The importance of intrusive rocks is enormous because they were formed from the same magma, which at the same time was a source of hot melts and solutions, during the solidification of which gold deposits appeared. In this sense, the presence of intrusive rocks serves as an indicator of the possible location of industrial ore bodies near them.

Gold is usually closely associated with sulfur compounds of non-ferrous metals and related minerals or with their oxidation products. These gold satellites are represented by chalcopyrite, pyrite, sphalerite, galena, arsenopyrite, stibnite, brown ironstone, etc.

Widespread satellite - chalcopyrite(copper pyrite) has a golden color with a metallic sheen and is very similar in appearance to gold in the rock. But even an inexperienced scout, without resorting to testing with acid, can easily recognize chalcopyrite by its higher hardness. Even harder than chalcopyrite, also similar to gold, its other companion is p i r i t(sulfur pyrite). They are valuable minerals: chalcopyrite-the main ore for copper, and pyrite used to produce sulfuric acid.

Sphalerite(zinc blende) has a black, brown or brown color, diamond luster. In quartz veins it is found mostly in the form of crystals, faceted with a system of regular planes. Scratched with a knife.

Galena(lead luster) is a silvery-white or gray mineral with a bright metallic luster, soft, heavy, almost twice as heavy as sphalerite. The cleavage is clearly expressed, and when struck with a hammer, the mineral crumbles along the cleavage cracks into regular cubes.

Arsenopyrite(arsenic pyrite) is a silver-white mineral with a metallic luster, hard to brittle. When hit with a hammer it will smell like garlic.

Antimonite(antimony luster) usually forms columnar and needle-shaped crystals or radial, often tangled clusters in quartz. The cyst is lead-gray, metallic luster. Soft and fragile.

Limonite(brown iron ore) - yellow-brown and dark brown in color. It is represented by a loose ocher mass or a lumpy sintered variety, often forming cubes along the pyrite. The most widely distributed mineral. Almost all quartz veins exposed to the surface are mottled in color due to limonite. Often the ocher mass fills voids in quartz formed in place of decomposed pyrite and chalcopyrite. Large masses of brown iron ore are observed at the outcrops of quartz veins rich in pyrite, chalcopyrite and other sulfides or on sulfide ore bodies.

Accumulations of brown iron ores on sulfide bodies are called iron hats And. They are of interest because they themselves may contain large quantities of gold.

Quartz is the main mineral with which gold is associated. Therefore, gold can most often be found in quartz veins.

Quartz can be very diverse in color: white, gray, milky white, smoky, yellowish, etc. It also varies in structure: fine-grained, coarse-grained, confluent, banded, concentrically layered (typical of chalcedony), sometimes with voids on the walls which can be observed crystals (druze) of transparent rock crystal. Visible gold can often be found in yellow-brown quartz with ocher inclusions.

Primary (ore) gold deposits are the primary sources of numerous gold-bearing placers. The composition of gold placers is determined by the composition of the primary deposits as a result of the destruction of which they were formed.

Often in gold placers there are found in the form of impurities latina, osmic iridium, tin stone - cassiterite, wolframite, titanium ore - ilmenite, diamond, rubin. These minerals also have a high specific gravity (except for the last two), and they resist abrasion and other types of destruction well when carried in a stream of water.

Most of the gold placers belong to alluvial, i.e., river ones, formed by the transfer and deposition of fragmentary material by channel flows and confined to the valleys of small and medium-sized mountain rivers.

There are placers where the bedrock ore bodies were not eroded after destruction and remained in the form of crushed stone, sand and clay at the site of their formation. Such placers are called eluvial: They usually occur on the wide, flat watersheds of modern rivers.

Placers are also found on mountain slopes, where gold-containing destroyed rocks accumulated, sliding down the slope from the bedrock deposit located above. Such placers are called deluvial: in terms of their industrial importance, they are much inferior to alluvial and even eluvial ones. It should also be noted the coastal-sea and lake placers, common on the coasts of seas and large lakes.

Other types of placers are known in nature, but they are of secondary importance.

Alluvial gold placers have the greatest value for industry. Depending on the conditions and location of placers, they are divided into channel, spit, valley, terrace and spoon.

Channel placers lie in the beds of modern rivers. These placers are characterized by a relatively small thickness of gravel-pebble sands and often a complete absence peat- deposits in which gold is almost never found.

Spit placers lie on spits, islands and shallows of modern large rivers. There is no peat on most spits. On spits, a significant proportion of gold is represented by very thin “floating” particles. A slight increase in gold is observed in the head part of the spit.

Valley placers are characterized by a greater thickness of sand and the presence of peat compared to channel placers. The total thickness is 5-10, and sometimes more than meters. Placers of this type occur in the floodplain and mostly on the first terrace of the river valley.

Terraced placers lie on longitudinal terrace-like ledges of bedrock that make up the slopes of river valleys. These placers are usually located above river level. At the same time, “high terraces are poorly preserved and are represented by narrow fragments on the slopes of valleys.

Spoon placers They lie in the valleys of ravines and small springs and rivers with intermittent water flow. Along with gravel and pebbles, the bedrock composition contains crushed stone and boulders. Many spoon placers start directly from bedrock deposits. Placers of this type are characterized by a high concentration of metal, which must be kept in mind when searching.

The sizes of placers are different. The largest number of them (about 60%) are no more than 3 km long; placers 3-10 km long account for 20-30%, and over 10 km - no more than 10%. Thus, the bulk of placers are usually located within the development of primary gold deposits or close to them in ravines, valleys or on terraces.

The age of placers varies greatly - from ancient to modern. The most ancient placers, as a rule, are composed of strong, firmly cemented rocks; deposits of young placers, the age of which does not exceed 60-70 million years, are usually represented by loose rocks.

For placers of all ages, the maximum concentration of gold is observed in the lowest layers of clastic (sand-pebble, often with boulders) deposits that lie directly on bedrock. In practice, the surface of bedrock underlying placers is called raft, and the gold-bearing layer is sands. Above the sands there is a practically non-gold-bearing layer called “peat”

The highest concentration of gold is observed at the very border of the sands and the raft. Particularly favorable places for the accumulation of gold are the uneven surfaces of the raft; protrusions of bedrock, cracks, depressions - pockets, funnels, etc. Along with gold, its satellites and other heavy minerals, such as magnetite, ilmenite, etc. accumulate here.

Gold as a precious metal has been used by humanity throughout its history. Its value is determined by the difficulty of extraction: it is difficult to find metal in nature, and even more difficult to extract it from rock. The history of mining the yellow metal has gone through several “gold rushes”, when prospectors in search of gold moved to new territories in North America, Australia and Canada in search of the precious metal and a better life. Similar events were typical for Russia in the 19th and 20th centuries, when the Siberian deposits and Lena gold mines were being developed. How is gold formed and how rare is the metal in nature?

Metal prevalence

Gold as a chemical element is found everywhere. The opinion that precious metal can only be found on the territory of deposits is incorrect. Gold is found in atomized form in plants and animals, as well as in the human body. The presence of metal in these cases can only be determined using special analytical methods. Gold is naturally found in the waters of the World Ocean; its concentration per ton of water ranges from 4 to 10 mg. This indicator is good, but there are currently no effective methods for extracting metal from the waters of the World Ocean.

The average content of the yellow metal in the crust of our planet does not exceed one millionth of a percent, so the threshold for the concentration of gold in the main rock, which allows us to consider a certain area a deposit, is also very low. Sometimes even a ratio of a quarter of a gram of precious metal per ton of rock may be considered beneficial for starting gold mining in that location.

Types of deposits

The global gold mining industry uses directly gold deposits and complex deposits containing the precious metal as a raw material base. How does gold appear? There are two types of metal deposits in nature: bedrock and alluvial.

Primary deposits are primary, since their appearance is associated with magmatic processes. The Earth's magma itself is characterized by a high concentration of precious metal. During the process of volcanic activity, it erupted onto the surface of the planet and then began to cool. But, since it contains many elements, cooling occurred unevenly. The most refractory substances crystallized first, then the more fusible components were shot into the surrounding rock, forming veins. The solutions of gold-containing salts were the last to cool.

The reasons for the presence of gold in nature in the form of alloys with other elements are also explained by magmatic processes. The composition of magma in different places could differ; the ratio of the composition components, as well as the conditions for the formation of veins, are not constant values. For this reason, different deposits differ from each other in the composition of the main rock and gold alloy, the shape and location of gold-bearing veins, and the conditions for mining the precious metal. The most common impurities in gold are copper, silver and platinum group metals.

Placer deposits are called secondary, as they were formed as a result of the influence of external factors on precious metal deposits in primary deposits. Gold in nature is released from rock as a result of its destruction due to temperature changes, wind, precipitation and the activity of microorganisms. The movement of the precious metal is facilitated by water, which erodes the rock, crushing it into small pieces and carrying away particles of gold. The yellow metal, due to its density, settles in certain places, while the remaining components of the rock are carried further by the water flow.

Based on the amount of precious metal reserves, primary deposits are divided into unique (more than 1000 tons), very large (100-1000 tons), large (100-400 tons), medium (25-100 tons) and small (less than 25 tons). What does gold look like in nature? The appearance of a precious metal during its extraction depends on the phase state of the element. Free gold is found in intergrowths with other minerals (most often with quartz), as well as finely disseminated in sulfides or rock minerals.

Placer deposits of yellow metal are divided into similar groups: unique (more than 50 tons), very large (5-50 tons), large (1-5 tons), medium (500 kg - 1 ton), small (less than 500 kg). Today, the reserves of placer gold are quite depleted, however, in Russia, the extraction of precious metals from such deposits accounts for about half of all metal production.

Metal nuggets

Gold occurs in nature in the form of nuggets. The photo of the most famous finds shows that large natural pieces of precious metal are usually called nuggets. Most of these incredible finds were made during the search for the yellow metal, although there were also accidental discoveries. Today, experts recognize a piece of gold as a nugget, the weight of which exceeds 5-12 g, and the cross-section is more than half a centimeter.

The most famous metal nuggets weigh several tens of kilograms. The largest nugget in the history of mankind is a piece of gold found in the 11th century in the southern regions of Afghanistan. According to the description that has survived to this day, it was supposed to weigh approximately 2.5 tons.

What does native gold look like in nature? Look at the photos of the most famous nuggets, among which you can note the “Holtermann Plate” (100 kg), “Welcome Stranger” (71 kg) and “Brilliant Barkley” (54 kg) found in Australia, and “Japanese” (71 kg) from the island of Hokkaido. The history of gold mining also includes finds from Russian deposits: “Big Triangle” (36 kg, Ural), “Bolshoy Tyelginsky” (14 kg, Chelyabinsk region), “Golden Giant” (14 kg, Magadan region), “Pokhod im. Kalinina" (14 kg, Ural), "Aprelsky" (12.24 kg, Lena mines).

“Holtermann Plate”.

Properties of gold in nature

Pure gold is characterized by a rich yellow color and bright shine, but such metal can only be found in the form of bank bars. Pure gold is practically impossible to find in nature, so its color in nature will depend on the size of the metal particles and the composition of impurities. Raw gold may have a grey-green tint, with an unattractive color accompanied by a dull luster to the metal. You can see what the precious metal looks like in this state in the photo of gold-bearing rocks. Sometimes the shine of precious metal particles in the rock may be completely absent. Yellow gold is found in nature much less frequently than the “green” metal. The unattractive appearance of gold particles means that usually only a specialist can determine the value of a find.

The precious metal is characterized by high thermal conductivity and low electrical resistance. One of the important properties of the metal can be considered its density: the weight of gold particles is the basis for the formation of placer deposits and most technological processes for its extraction.

Placer deposits of gold in nature exist due to the fact that heavy particles of the metal settled along their path in streams of water, and light rock was destroyed and washed away. The high density of the precious metal is used in the washing process at sluices, since it is this physical property that ensures high rates of metal recovery from the washed rock.

The high reflectivity of the element allows the use of the thinnest sheets of metal in the production of office glass, glass for aircraft and watercraft, and helmets for astronauts. The production of thin sheets of gold is possible due to its excellent malleability and easy polishing.

Gold in nature is chemically inert. The metal does not react with other elements, which is why it was classified as noble. Among the known chemical reactions in which aurum enters, one can note the dissolution of the metal in “aqua regia” and hot selenic acid of high concentration. The precious metal reacts with oxygen in the presence of complexing agents, which can be cyanide.

The yellow metal is able to react with fluorine, but only at a temperature of 300-400 degrees Celsius: at lower parameters the reaction does not take place, and at higher parameters the resulting fluorides begin to decompose. Another well-known reaction of gold is its dissolution in mercury to form an amalgam.