Marquise

Gold mining includes exploration, drilling, geology, refining and refining to extract gold from the mines of this metal. Sources of gold element for mining are open, underground and alluvial. The gold mining process includes the following general steps.

Mining discovery: Mining discovery may take between 1 and 10 years and requires financial resources and the use of experts in the fields of geography, geology, chemistry and engineering. Less than 0.1% of the discovered mines have the potential to be developed and mined.

Mining development: Mine development is the second stage of gold mining. For mine development, planning, mine construction and necessary infrastructure are needed.

Extraction operation: The operation of extracting the element of gold includes mining, gold processing and converting the extracted ore into a metal alloy with a purity of 60 to 90.

closing the mine: After the end of mining and mine activity, the operation of mine closure and land reconstruction is done.

Resuscitation: After the closure of the mine, the environment should be cleaned of pollution and vegetation and soil should be restored as much as possible to reach stability.

Extracting gold from its ore includes crushing, processing minerals and applying hydrometallurgy and pyrometallurgy processes on the extracted ore. Gold was extracted from alluvial rock sources with placer methods. In hydraulic mining, water pressure is used to break alluvial deposits.

Extraction of gold element by carbon absorption

Extraction is done by using activated carbon porous matrix and absorbing gold in it. To separate the gold absorbed in the carbon matrix, a strong solution of sodium hydroxide (NaOH) and cyanide are used for elution.

Mercury process for elemental gold

Small-scale gold extraction is done using mercury and the formation of mercury-gold amalgam, but due to mercury pollution on a large scale, the use of this method has been stopped.

Gold element mining pollution

5 tons of gold ore are needed to extract only 10 grams of gold. The process of digging the ground, the use of heavy machinery for transportation and the use of chemicals such as mercury and cyanide cause damage to the environment. The environment of gold mining mines suffers a lot due to the construction of dams on rivers, deforestation and removal of mountains.

Uses of gold

Gold, when used as a coloring agent in cranberry glass, produces a deep, intense red color.

In photography, gold toners are used to change the color of black and white silver bromide prints to brown or blue colors or to increase their stability. Gold toners used in brown prints produce red colors. Kodak published formulas for several types of gold toner that use gold as chloride.

Gold is a good reflector of electromagnetic radiation such as infrared and visible light as well as radio waves. It is used for protective coatings on many artificial satellites, in infrared shielding plates in astronaut thermal suits and helmets, and in electronic warfare aircraft such as the EA-6B Prowler.  Gold. is used as a reflective layer in some high-end CDs.

Cars may use gold for heat protection. McLaren uses gold leaf in the engine compartment of its F1 model.

Gold can be made so thin that it appears translucent. In some airplane cabin windows, it is used for defrosting or anti-icing by passing electricity through it. The heat from the gold resistance is enough to prevent ice from forming.

The gold is attacked and dissolved in alkaline solutions of potassium or sodium cyanide to form salt gold cyanide – a technique used in the extraction of metallic gold from ore in the cyanide process. Gold cyanide is the electrolyte used in commercial gold plating on base metals and electroforming.

Gold chloride (chloroauric acid) solutions are used to make colloidal gold by reduction with citrate or ascorbate ions. Gold chloride and gold oxide are used to make cranberry or red glasses, which, like colloidal gold suspensions, contain spherical gold nanoparticles of uniform size.

When gold is dispersed in nanoparticles, it can act as a heterogeneous catalyst for chemical reactions.

Other uses of gold include:

• Using gold toners in photo printing to change black and white to brown or blue colors
• Making a Gold Compact Disc
• Heterogeneous Gold Catalysis in the form of nanoparticles

From the applications of gold in medicine Apart from medical uses such as making medicines and such, we can mention the making of surgical instruments, use in some artificial parts of the body, the making of some laboratory equipment such as accurate thermometers, etc. 

Gene therapy with gold element

Gold nanoparticles are used in gene therapy, which is a method of treating disease through the repair of defective genes.

Photothermal therapy

Gold nanorods have been used as photothermal agents in photothermal therapy (PTT) research. In this treatment method, electromagnetic radiation, which is usually in infrared wavelengths, is used to treat various diseases, including cancer.

Biosensor

The use of gold nanoparticles in biosensors increases their stability, sensitivity and selectivity. These types of sensors are divided into two main groups: optical and electrochemical biosensors. In electrochemical sensors, biological data is converted into electrical signals.

Gold in dentistry

The relatively good malleability of gold alloys and the ineffectiveness of this element have led to its use in dentistry. The gold element is used in dentistry to restore and cover teeth.

The medicinal use of gold in the form of metal has been popular since ancient times. In the 19th century, this metal was used to treat anxiety, nervous disorders, depression, epilepsy, migraine, amenorrhea, impotence and alcoholism.

In fact, the gold element does not react with any of the chemicals in the body and is ineffective against them, and only its salts and isotopes have medicinal value. For example, stomach acid has no effect on gold.

Medical Imaging

Thin gold coatings are used to observe biological or biological samples and other non-conductive materials such as plastic and glass in the Scanning Electron Microscope (SEM). When gold is irradiated, it produces a lot of secondary electrons. Secondary electrons that have low energy are one of the signal sources of scanning electron microscope. The emission of these electrons is the result of charged particles such as electrons or ions hitting the metal surface in a vacuum tube.

Quick Diagnosis

Colloidal gold is used in the immunogold labeling or staining method (Immunogold labeling | IGS) in the electron microscope for rapid detection or immunoassay. By using this method, colloidal gold particles coated with special antibodies with the characteristic of surface absorption of protein molecules can explore the presence and position of antigens or antigens on the surfaces of cells. These particles can be seen with an electron microscope in highly sensitive findings in the form of dense dots where antigens are present.

In nuclear medicine of 198 Au isotope  whose half-life is only 2.7 days for the treatment of some cancers use. Colloidal nanoparticles are used in cancer research to detect tumors using Surface-enhanced Raman Spectroscopy (SERS).

Drug Delivery

Gold nanoparticles are used in drug delivery to optimize and improve the targeted biodistribution of drugs in organs, tissues or cells. Drug delivery includes unstable drug targets such as proteins, tumors, intracellular organelles, hard-to-reach locations such as the brain, retina, and drugs with serious side effects such as anticancer drugs.

The amount of gold used in the industry is about 10%, and its most important use is in the electronics industry. Corrosion resistance, electrical conductivity, malleability and non-toxicity are the advantages of using gold in industry.

Gold is used in this industry to make electrical connectors in computers and other electrical devices such as communication equipment, spacecraft, and jet engines. For example, about 50 mg of gold is used in making a normal mobile phone.

Features such as good conductivity and resistance to oxidation and corrosion in non-chlorine environments have made this element widely used to cover electrical connection equipment. It is used in the construction of electronic cable connections such as audio, video and universal serial bus (USB) cables. Very fine gold wires are used in the connection of semiconductor parts using the wire bonding process. Because of their high conductivity, gold, silver and copper are mainly used for electrical wiring and transmission of electricity, and the advantage of gold over silver and copper is corrosion resistance. .

In this video, Marquise jewelry accounting software is introduced, as well as its capabilities and challenges.

The important competitive advantages of Marquise have been business knowledge, detailed analysis and software design based on market needs.

When Marquise started to grow, famous brands such as TAJ, Kia, Parasteh, Ruby, etc. started to grow alongside Marquise.

Identifying real gold with the skin of the body

In this method of detecting gold from fake, which can be said to be one of the easiest ways to quickly detect gold, just put the gold in contact with your skin and look for a bluish or green color on your skin.

It is very easy to recognize real gold by skin: you can hold a piece of gold jewelry between your hands for a few minutes. The sweat on your hands will either react with the gold metal and change the color of your skin or leave it unchanged.

In fact, in this gold diagnosis method, we should know that when gold is in direct contact with your skin, color change does not occur. If the gold is fake, it will cause your skin to turn black, blue or green at the contact points.

There is an exception to this gold detection method, and that happens when you test gold on your skin while using liquid cream powder. Keep in mind that when gold gets into makeup, it will darken your skin at the contact points. To quickly detect gold, it is better to remove all cosmetics before the gold test.

If we buy gold online, how can we ensure its authenticity?

These days, apart from the traditional gold shops in the markets, you can also buy gold and jewelry online. But the question is, how and with what confidence can we buy gold from online gold shops?

it's simple. There are ways that you can be aware of the authenticity of gold or the safety of buying from online gold shops. For example, suppose you want to buy a gold bracelet and you go to buy it on an internet site. To make sure that the gold is genuine and your purchase is legal and without fraud, pay attention to the following points:

• The site where you buy gold must have official permits to buy and sell gold from the Gold Dealers Union.
• The site must have an electronic trust mark.
• All contact numbers and addresses of gold shops must be listed on the site.
• Each of the products in the store must have a birth certificate and a warranty.
• There is a possibility of returning the product and your payment if the product is fake.

How to test the authenticity of gold with a lighter?

Detecting gold by burning is one of the very simple ways to detect gold from change at home. The detection of gold by burning is in such a way that you first set fire to the gold and try to burn your gold. If your gold is real, it will brighten with the flame, but it won't actually catch fire or burn. If your gold piece starts to smoke or darken, you probably have fake gold and you've easily tested the gold standard at home.

It is interesting to know that real gold does not burn and darken under heat and simply melts; That is why it can be molded and made into different shapes without losing its luster and beautiful golden yellow color.

On the other hand, other metals such as copper, iron and brass change color and become darker when exposed to flame. If your item is only gold plated, the gold plating will melt and you will see a darker metal underneath.

Determining the grade of gold with a touchstone

To determine the purity percentage of Talajat, first we draw the metal suspected to be gold (20 times) on the touchstone and then we draw some refined Soltani water on it.

Identifying real gold with water

The easiest and cheapest way to distinguish gold from other metals is to use water. In this method of identifying gold, you can throw your jewelry in water, if the gold remains on the bottom of the container and does not float, you can be sure that your gold is genuine.

Real gold detection with Vitex

Another way to distinguish gold from rhinestones is to use Vitex. Of course, before explaining this method, it should be mentioned that detecting gold with Vitex causes corrosion in gold. Therefore, it is not recommended to use this method. To do this method, it is enough to pour a very small amount of Vitex on the gold. If you notice the color of the metal changing to red, green or brown, your gold is genuine; But if the desired metal turns black, it indicates that it is fake.

Detection of real gold with iodine

You can check the authenticity of gold with iodine. Apply a little iodine on the surface of the gold, if the trace remains, the gold is fake. But if it is lost, your jewelry is original. If you put a drop of iodine on platinum and it leaves a dark mark, the darker the platinum, the purer it is..

Identifying real gold with ice

Gold and silver are very strong conductors of heat compared to other metals. If you put your gold and silver on a piece of ice, the melting speed of the ice will increase so that you think you have placed a hot object on it, so you can use this method to identify the original gold and silver.

Identification of real gold by weighing

If you have recently bought a gold bar, but you are worried that you have bought fake gold instead of real gold, you can weigh it to find out. First, put the ingot on an accurate scale and measure its weight. Then fill a container with water, place it on the scale and set the weight indicator to zero. Immerse the ingot completely in the water and weigh it again. To find out, just divide the first number by the second number. If the obtained figure is 32.19, you have bought pure gold.

Detection of real gold with nitric acid

A definitive method for detecting gold is the use of nitric acid. Place your jewelry in a stainless steel container. Pour a drop of nitric acid on it, if they do not react with each other, your gold is genuine. But if the color of the drop of nitric acid turns green or brown due to the reaction, your gold is fake. Note that nitric acid damages your jewelry. In addition, because nitric acid is dangerous, it is better to leave this to an experienced goldsmith.

Detection of real gold with alcohol

Alcohol is one way to distinguish real gold from fake. Gold detection with alcohol is another widely used home method to check the authenticity of purchased gold. Most metals change color in the presence of alcohol; For this reason, when buying replacement jewelry, the buyer is asked to keep these jewelry away from alcohol and water in order to prevent the color change and deterioration of the appearance of these rhinestones. For this reason, you can use the method of detecting gold with alcohol to find out whether your metal piece is genuine or fake.

In the gold test with alcohol, you can dip part or all of your metal piece in alcohol. Since alcohol vaporizes in the presence of air, you only need to spray a small amount of alcohol on the metal piece and you do not need to immerse the metal in alcohol. If you plan to immerse the piece in alcohol to be sure, you should use a closed container.

If you use immersion method and only 5 minutes is enough to detect gold with alcohol. If after 5 minutes your metal does not change color and does not turn black, it is original; But in the spraying method, you should spray some alcohol to the metal piece at least two to three times at different time intervals. After a day, if no color change is observed, you can be sure that the gold is original.