GOLD

Gold is the most popular precious metal for investments. It has been known to humans for a very long time, with archaeological finds dating back to the Neolithic era, around the V-IV millennium BCE. Wars were fought, lands were conquered, nations were destroyed, and new territories were explored for the possession of gold. Its history is closely intertwined with the history of humanity.

Gold is a prevalent element in real life, even in minuscule amounts found in plants and the bodies of humans and animals. There is a relatively high concentration of gold in seawater, but there is currently no effective method for extracting it. Gold is extracted in the form of nuggets, sand, and veins.

Properties of gold: The Latin name of the chemical element “gold” in Mendeleev’s table is Aurum (Au), meaning “shining dawn.” It has a melting point of 1064.4°C and a boiling point of 2880°C. Gold is considered a noble metal due to its high inertness—resistance to the influence of other elements and compounds. Pure gold usually reacts only with mercury, making gold jewelry resistant to chemical changes in everyday conditions.

Gold is characterized by:

• High softness, ductility, malleability, and tensile strength, making it easily processed in various ways.
• High density and weight, utilized in gold extraction.
• Low electrical resistance, contributing to its use in electronic devices.
• High polishability and reflectivity.
  
  

A 1mm-diameter gold sphere can be flattened into an ultra-thin sheet, exhibiting a bluish-green color, with an area of 0.5 m2. The thickness of the thinnest gold leaf is 0.1 µm. Gold can be drawn into extremely thin threads.

Gold is one of the heaviest metals, with a density of 19.3 g/cm3. Only osmium, iridium, platinum, and rhenium are denser than gold. A 3.7 cm cube of gold weighs 1 kg. A cubic meter of gold weighs 19,320 kg, while the same volume of iron weighs nearly three times less at 7,874 kg.

If a room with an area of 20 m2 and a height of 3 m is densely filled with gold bars, the mass would be 1150 tons—equivalent to the weight of a heavily loaded train.

One natural form of gold is in the shape of nuggets. Nuggets are not just sand; they are solid pieces of metal with arbitrary shapes, varying in size from a few grams to several kilograms. Nuggets contain varying amounts of impurities.

Unprocessed gold, which has undergone initial washing to remove light mineral particles, is called “slag.” This metal is then subjected to melting and purification. Gold refining is the process of purifying it from impurities, using various technologies based on its physical and chemical properties. Depending on the complexity of the processes and safety measures required, purification can be done in ordinary households, laboratories, or industries.

Purity of gold:

Pure gold always has a yellow color. However, because pure gold is too soft for most jewelry, it is alloyed with other metals to increase hardness. The color of the alloy depends on the amount of added impurities. Jewelry gold typically contains copper, zinc, silver, nickel, platinum, or palladium. The metal added to gold is called the “alloy.”

The quality of a gold alloy is assessed using a hallmark system. This system indicates the amount of pure gold in the item and guarantees this content. There are two prevalent systems: the carat system and the metric system, both based on the same principle.

The carat or hallmark in gold depends on the presence of foreign metals. For example, 24-carat gold is nearly pure, comprising 99.9–100% of the alloy’s total mass. In the metric system, this corresponds to 999.9 purity. The difference between the two hallmark systems lies in the fact that in the carat system, the entire alloy (gold + impurities) is considered as 24 parts, while in the metric system, it is considered as 1000 parts. To find the metric hallmark corresponding to the carat hallmark, divide the carat value by 24 and multiply by 1000.

24-carat (999.9 purity) gold is very soft. Due to its increased deformability, it is rarely used in items requiring wear resistance and strength, such as jewelry. Therefore, a ligature is introduced into the pure metal, which can be platinum, silver, nickel, copper, palladium, zinc, cadmium, or other elements. For example, 585-carat gold means that out of 1000 units in the alloy, 585 are pure gold, and 415 are ligature.

It’s worth noting that the term “carat” is not only used to denote the content of pure gold in an alloy but also for the weight of diamonds and other precious stones. These two concepts should be distinguished. In the former case, the term “carat” is used, and the value is recorded as, for example, “18k” (18-carat) or “14k” (14-carat). In the latter case, “carat” is used with the abbreviation “c” or “ct.”

Standard gold bars held by the world’s governments have a purity of 999.9. While pure metal without impurities corresponds to 1000 purity, gold bars are not in a vacuum and can react chemically with air. Due to the addition of any extra elements, the purity of a gold bar is considered not as 1000 but as 999.9.

Gold is a commodity traded on the exchange. It has its own standard code, similar to currencies; typically, it is denoted as XAU. The main exchange platforms are the London Metal Exchange (LME) and the New York Stock Exchange (NYSE). Prices are quoted in troy ounces, equivalent to 31.1 grams. As of the summer of 2023, the price of gold is within the range of $1,915 per ounce. (For the price chart over the last 10 years, you can find it online.)

The primary factor influencing pricing, aside from the supply and demand ratio in the jewelry and other industrial sectors, is the state of the global economy. Investors consider gold a reliable alternative for currency investments.