How did the gold rush begin

19.8.1849

It happened on January 24th of last year in a sawmill on the American River: While building a sawmill, James Wilson Marshall discovered a gold nugget. Although attempts were made to keep the find a secret, the story quickly got around: There is gold on the American River!

Soon the first gold prospectors from all over California were crowding the river. Thousands of workers in San Francisco quit their jobs and came to make their fortune on the riverside. But not only the inhabitants of the country were seized by the gold fever. More than 50,000 people from Mexico, Chile, China and especially from Europe poured into California and flooded the cities here. The Great Migration in San Francisco in particular was bursting at the seams. In just one year since the first gold nugget was discovered, California's population has now grown fivefold.

The immigrants have great hopes, and the yield from panning for gold is often low. With a bit of luck you can earn a lot more here than a worker on the east coast receives as wages, but life in the gold rushes is expensive. Simple groceries have to be bought at exorbitant prices. An egg costs a dollar, a newspaper even ten! In addition, some gold miners celebrate their new wealth by gambling or with alcohol in the saloons. For some, the gold rush has already ended with a bad hangover.

Wash gold - how are you?

The technique of the Californian gold prospector is simple: The search doesn't take much more than a tin pan and a leather bag. Sand and silt from the river are shoveled into the pan. When the pan is swiveled, water and sand are washed up to the edge. Now it's getting exciting: with a lot of luck, small pieces of gold will flash at the bottom of the pan. Because they are heavier than the rest, they stayed in the middle. The gold pieces can be collected in a leather bag and you can move on to the next pan. Good luck!

28.1.1905

A rough diamond was found in a mine in South Africa on Thursday, which is larger than all known diamonds on earth. This record gem weighs a total of 3106 carats. He was discovered by Frederick Wells, the mine inspector.

It happened in the late afternoon during a routine inspection of the Premier Mine near Pretoria. On his tour of the mine, Frederick Wells saw something light up above him. Wells became curious and took a closer look. Could that dazzling thing really be a giant diamond? He managed to pull the stone out of the wall and still wasn't sure if it wasn't a piece of glass that was making a fool of him. However, research could prove that he was really dealing with a diamond. And with the largest one that has ever been discovered on earth. The valuable chunk has exactly 3106.75 carats. That corresponds to a weight of 621.35 grams or a little more than 6 bars of chocolate.

For his sensational discovery, Frederick Wells is now to receive a "finder's reward" of $ 10,000. The name giver for the greatest diamond of all time is mine owner Sir Thomas Cullinan: The famous “Cullinan diamond” is already being talked about everywhere.

The "Immortal"

Its sparkle drove many people crazy - or at least a fortune. No wonder, because the diamond is the most valuable of all gemstones. And not only that: it is the hardest known mineral. That is why the dazzling top carat is also called “the immortal”. Myths and legends surround this rare jewel. Famous diamonds such as the "Hope" or the "Florentine" are said to have a curse that brings bad luck and death to their owners. Others, however, see the diamond as a symbol of eternal love, wealth and power.

Gemstones

Whether green emerald, blue sapphire or red ruby: we know precious stones as sparkling and particularly valuable pieces of jewelry. Gemstones are simply minerals. However, they have to meet three requirements in order to be considered gemstones: They have to be particularly rare, transparent and at the same time very hard.

Gemstones are formed deep in the earth's interior under high pressure and at high temperatures. The hardest of them and at the same time the hardest known mineral is diamond. It is formed from a single element at a depth of around 150 kilometers at temperatures above 1200 degrees Celsius: carbon. Crystals usually develop from eight equilateral triangles, called octahedra. Other shapes such as cubes are also possible. The diamond gets to the surface of the earth by being thrown upwards together with the rising magma. The largest diamond ever found is the so-called "Cullinan". It was discovered in a South African mine in 1905 and weighed exactly 3106.75 carats in its raw state. This corresponds to a weight of 621.35 grams.

Whether diamond, amethyst, emerald or topaz - all gemstones differ from one another in terms of structure, composition and color. They only become particularly beautiful and shiny when they are cut. He lets the colors of the gemstones shine properly through a certain refraction of light.

In addition to precious stones, there are other gemstones in the earth's crust, such as blue lapis lazuli or green malachite. Although these are also very sought-after and beautiful, they are not see-through and are too common to be considered gemstones.

From inside the earth: ores and solid metals

Copper was the first metal that humans discovered in the earth's crust. It could be shaped into simple tools or weapons and was so important that an entire epoch was named after it: the Copper Age. The tools got better when man mixed the copper with tin and thus invented the bronze. And when he learned to smelt iron, the triumph of metal tools finally began.

Unlike the core of the earth, the earth's crust consists largely of non-metals. Nevertheless, metals such as iron, aluminum, manganese and potassium can be found in their rock. Experts (geochemists) can determine exactly how often they occur. They found out that around seven percent of the earth's crust consists of iron.

Like most metals, iron occurs as a chemical compound with other elements, so-called ore. In order to extract iron from the ore rock, the ore rock is ground, mixed with coal and heated. Then a chemical reaction takes place that removes the other elements from the ore, leaving the pure, elemental iron.

On the other hand, some metals hardly combine with other elements. They therefore do not weather and occur in pure form in the earth's crust. These “solid metals” include gold, silver and platinum. Platinum and gold are also extremely rare: on average, gold is only contained in a ton of rock with an average of 0.001 grams. A place is only referred to as a deposit if it contains a thousand times the amount of gold - i.e. one gram of gold per ton of rock.

The "rare earth metals" are more common than gold or platinum. What sounds strange has a simple reason: These metals are considered rare because they do not form deposits of their own, i.e. they do not occur in concentrated form, but only in scattered areas. We are therefore also talking about spice metals. Their importance has increased significantly in recent years because they are required for the manufacture of electronic devices such as cell phones or computers.

From rock to grain of sand - weathering

Today the north of Canada is a gently undulating landscape. However, many million years ago there was a mountain range here. In fact, even high mountains can turn into small hills over a very long time.

The reason for this transformation: The rock on the earth's surface is constantly exposed to wind and weather. For example, if water penetrates into cracks in the stone and freezes, it splits the stone apart. This process is called frost blasting. The rock also becomes brittle through temperature changes between day and night and through the force of water and wind. In other words: it weathers. This process can also be observed in buildings or stone figures. During the weathering, the rock breaks down into smaller and smaller components up to fine grains of sand and dust. Different rocks weather at different rates: Granite, for example, is much more resistant than the comparatively loose sandstone.

Some types of rock even completely dissolve when they come into contact with water, for example rock salt and lime. Rock salt is chemically the same as table salt - and that already dissolves in ordinary water. Lime is a little more stable, but limestone also dissolves in acidic water. Acid is formed, for example, when rainwater in the air reacts with the gas carbon dioxide. This “acid rain” attacks the limestone and dissolves it over time. The weathering leaves rugged limestone landscapes on the surface of the earth, and caves are formed below the surface.

But not only solution weathering, heat and pressure also wear down and crumble rock under the earth's surface. Wherever plants grow, roots dig in, break up the rock piece by piece and also ensure that it is removed millimeter by millimeter.

In this way, weathering not only works on individual rocks, it gnaws at entire mountain ranges. It will take a few million years for the Black Forest to be as flat as northern Canada.

The outermost shell of the earth

Like an egg from an eggshell, the earth is also surrounded by a hard shell. This outermost layer surrounds the earth's mantle and is called the earth's crust. If you compare the earth to a peach, the earth's crust is - in relative terms - as thick as its skin. Under continents it reaches an average of 40 kilometers deep, under the oceans it is only about seven kilometers.

Below is the outer part of the earth's mantle, which extends to a depth of around 100 kilometers. It is also solid, but consists of heavier rock. The earth's crust and this outermost part of the mantle together are also called the “lithosphere”. This solid layer of rock has broken into slabs of different sizes, which slowly drift around on the hot, viscous mantle of the earth.

Where the rock melt penetrates upwards from the hot earth's mantle, the earth's crust can break up. Then lava flows out, which becomes the new crust of the earth. This mainly happens where the plates of the lithosphere adjoin one another, such as on the mid-ocean ridges.

In Iceland, for example, these plate boundaries are easy to recognize: cracks and furrows run through the earth's crust, where the Eurasian and North American plates drift away from each other. There is also a plate boundary in the Mediterranean region. Because the African plate is pressing against the Eurasian plate here, there are many volcanoes in Italy and there are always earthquakes.

The crust is covered by the bottom. The soil of the land masses is formed from weathered rock and remains of animals and plants. The sea floor, on the other hand, develops from deposits such as clay and sunken remains of marine organisms. On the coasts, the sea floor also consists of deposited rubble that was removed from the mainland and washed into the sea.

Bottoming out

Plants rarely grow on bare rock. They need a soil from which to draw nutrients and in which to form roots. Weathering is necessary for such a soil to develop: rain and oxygen, heat and cold, water and wind grind the rock and grind even hard granite into smaller and smaller grains. What comes out of this is what is known as weathering debris.

But thousands of years will pass before it becomes living soil. Bacteria, fungi and lichens are the first to settle on the rock; the first soil animals are attracted to it. Dead plant remains, animal carcasses and excrement gradually mix with the crushed rock. From this mix, with the help of fungi and bacteria, the upper soil layer develops from fertile soil on which plants can thrive. There are other layers underneath, for example made of sand or clay. At the very bottom lies the rock from which the soil develops.

Depending on which rock is weathering, how moist it is, which plants are growing and which temperatures are prevailing, different soils with different properties and colors are created. Whether weathered rock is washed away or deposited also plays a role.

In our temperate latitudes there are often the brown earths. They develop on rock with little or no lime in a humid climate. The Rendzina, a soil that forms on limestone, is dark in color. Because it is so stony, it is difficult to farm on it. And on the Italian island of Stromboli there are very special sandy soils: Because the lava rock that comes from the Stromboli volcano is dark, the sandy beaches on the volcanic island are pitch black.