What is Gold?
Gold is a chemical element with the symbol Au and atomic number 79. Pure gold is recognized by its bright yellow color, slightly reddish or white. Gold naturally forms and is found in nature either in its pure form or combined with elements like silver, copper, palladium, and tellurium.
Since the beginning of human history, when people first discovered gold, they realized its value. The rarity and beauty of this material, combined with its special properties, made it a popular material for humans. Gold is perhaps the most commonly used material extracted from mines. In addition to jewelry and coin production, this shiny and valuable material is used in the manufacturing of electronic components, medical applications, and both small and large industries.
How is Gold Formed?
All the gold on Earth comes from the remnants of dead stars. During the formation of the Earth, heavy elements like gold and iron sank into the Earth’s core. While we are unsure how gold in the Earth’s core reached the mantle and crust, scientists believe that about 4 billion years ago, the Earth was bombarded by asteroids and meteors. As a result of these impacts, elements from the Earth’s core reached the surface.
Gold is scattered across the Earth’s surface in various rocks and environments, where it may be pure or mixed with elements like silver, copper, or palladium. This combination of gold with other metals is called native gold.
The erosion of gold-bearing rocks gradually releases this element. Since gold is a heavy metal, it settles in riverbeds, alluvial deposits, and even oceans. Recent studies suggest that some microbes play a crucial role in accelerating the formation of gold nuggets and particles.
Earthquakes, along with the evaporation of water rich in minerals like silica and gold, leave elements in fault fractures that contain gold. How? When an earthquake occurs, water infiltrates the Earth’s surface, and the temperature and pressure conditions at this depth cause the water to suddenly evaporate, turning silica into quartz. Gold remains as veins.
In alchemy, there have been rumors about turning lead into gold, but it’s better not to believe such claims because converting elements into one another requires chemical processes to change the number of atoms. The number of atoms defines an element’s identity, and we cannot change them!
Ways to Identify Gold Ore:
Some rocks and minerals found in nature closely resemble gold and might be mistaken for this valuable material. To identify gold ore, we need to recognize its characteristics. The luster of gold nuggets is one of the most important ways to identify gold ore. Gold has a shiny, metallic luster, and the nuggets found in nature are not dull or opaque. Another point to remember is the color of gold. Gold is yellow to golden in color and is often combined with silver in nature. The more silver there is, the whiter the gold becomes.
One of the most important characteristics to remember when identifying gold ore is its appearance. Gold rocks found in rivers usually have rounded edges, and in rare cases, they may have a crystalline shape. If you find such a rock, raise your hat because it will be very valuable and expensive! Gold crystals do not have straight growth lines, which is a good way to distinguish gold ore from similar rocks, which mostly have parallel, straight lines.
Gold is also heavier than other materials that resemble it due to its high specific gravity. Another way to identify gold ore is by its streak color, which can be obtained by rubbing it on an unglazed ceramic plate. Gold’s streak color is always yellow and golden, while copper’s streak is reddish copper, and pyrite’s streak is green. Gold pieces are very flexible and can easily bend under pressure, while similar materials like pyrite are brittle. Additionally, gold particles in nature can be cut with fine tools, which is not the case for similar metals.
How to Know if Soil Contains Gold?
To determine if soil contains gold, the following steps should be taken:
Mineralogical Analysis of the Rock or Soil: Since gold is often found in association with certain other elements, it’s important to conduct a mineralogical examination to identify potential gold-bearing minerals.
Fire Assay Analysis: This method is used to measure the total amount of gold present in the sample. It is a highly accurate process that involves melting the sample and separating the gold.
Aqua Regia (Royal Acid) Analysis: This method helps detect gold that is bound to sulfides. Aqua regia is a mixture of hydrochloric acid and nitric acid that dissolves gold.
Cyanide Analysis: Cyanide is used to determine the amount of gold that is soluble in the solution. This method is especially useful for detecting gold in its more soluble forms.
How to Identify Gold Ore in the Mountains and Conduct Fieldwork?
For fieldwork and identifying gold ore in mountainous regions, here are a few practical steps you can follow:
Look for Indicator Minerals: Gold is often found in specific mineral deposits, such as quartz veins or pyrite. These minerals can indicate the presence of gold. When searching in mountainous regions, you should look for quartz outcrops and pyrite-rich areas.
Pay Attention to Alluvial Deposits: Gold tends to settle in riverbeds, streams, and valleys due to its high density. The closer you are to riverbeds, especially in areas where gold is known to have been mined, the more likely you are to find gold in the soil.
Conduct Panning: A basic and effective field method for detecting gold in streams is gold panning. By washing the sediment in a pan, you can separate heavier particles, such as gold, from lighter particles. This method gives an immediate visual clue if gold is present.
Look for Gold Veins or Quartz Deposits: Gold is often found in quartz veins within mountainous areas. You can identify quartz veins in the rocks and check if gold is visibly present within them.
Use Metal Detectors: Metal detectors can be helpful in detecting gold nuggets or gold-bearing ores, especially if the gold is large enough to be detectable.
In the field, these methods can help you get a rough idea of where gold might be present, but for more accurate results, laboratory testing and detailed analysis are required.
Is it possible to detect gold soil with bleach and hydrochloric acid?
Short answer: No.
Hydrochloric acid by itself is capable of dissolving metal oxides like iron oxide, copper, and lead, but it cannot dissolve gold. Similarly, bleach cannot dissolve base metals or gold by itself. However, when combined with hydrochloric acid, bleach can act as an oxidizer, helping to dissolve gold. This method allows for detecting gold-bearing rocks using bleach and hydrochloric acid, followed by field tests with tin chloride for further verification.
What Color is Gold-Bearing Soil and How Can It Be Identified?
Soil containing gold usually exhibits a distinctive color, which can be an important indicator. As mentioned earlier, soil color is one of the signs for identifying gold in the soil.
Several reasons contribute to this phenomenon. The first reason is the presence of minerals that are found in the host rocks or adjacent to gold. Each of these minerals can affect the soil’s color. For example, iron can turn the soil red, yellow, or brown, while quartz can lighten the soil.
Other minerals like pyrite and copper are also associated with gold and can influence the soil’s color. If the soil takes on unusual colors like dark green or orange, it’s a strong signal that further analysis is needed. There’s a high chance that gold may be present based on further examination.
Additionally, environmental factors like natural acids from underground deposits can brighten the soil’s color. Soils with these unique colors are likely to carry gold because gold dissolves in such environments and accumulates in fissures.
Natural processes, like erosion, can also change the color of the soil. Soil subjected to natural erosion may change its color due to the release of gold particles from the parent rock.
In any case, soils with distinct colors are prime candidates for gold detection. It’s best to conduct a thorough investigation of such soils when searching for gold.
Where is gold-bearing soil found?
Gold-bearing soil refers to soil that contains gold particles. Many people are curious about where such soil can be found. The answer is that gold-bearing soil is typically found in areas where geological and chemical processes have occurred.
Gold-bearing soil is more likely to be found in the following locations:
Alluvial deposits in rivers, streams, or seas
Mineral-rich rocks and mountainous areas
Soils rich in minerals (the methods for detecting these were mentioned earlier)
Around commercial gold mines, due to the pulverization of gold during extraction, which then mixes into the surrounding soil
Areas with volcanic activity or heat events, which can create conditions that concentrate gold particles
Gold Extraction from Soil
Once analysis confirms that gold has been found in a suspicious sample, the next step is extraction. Gold extraction refers to the process of separating gold from gold-bearing minerals.
The goal is to extract gold as a final product that is marketable. Extraction involves several stages and is carried out using various methods, requiring industrial and mining equipment like washing machines, furnaces for melting, and processing machinery.
Which method is most suitable for extracting gold from soil and rock?
The choice of extraction method for gold from soil and rock depends on several factors. The condition of the mine must be assessed, and costs should be considered. Additionally, the concentration of gold in the analyzed samples also plays a role in selecting the extraction method, as some methods only work well with higher concentrations of gold.
Furthermore, environmental needs and economic conditions should not be overlooked. For example, the hydraulic method, although it can process large amounts of soil at once, leads to soil erosion and damages local ecosystems. Additionally, this method requires accessible water resources, which may not be available in many geographic areas.
In general, before selecting a method for extraction, it is crucial to conduct a thorough, specialized evaluation and consider all aspects of the situation.
Final words:
Gold exploration and extraction is a complex process. From the initial search to the point when pure gold is extracted, a great deal of energy and time will be invested. It’s important to learn the practical methods of detecting gold in rocks and soil and combine them with modern analysis and extraction techniques to achieve success.
In this article, we have explored methods for detecting gold in rocks and soil, and we highlighted signs that indicate the presence of gold in an area. After that, we examined various analysis methods and compared their advantages and disadvantages. We also discussed different gold extraction methods from soil and rock. Finally, we presented an investment opportunity for you, encouraging you to invest in gold exploration to stay ahead in the gold investment game. We hope all of this information helps you achieve your goals.
