Gold (Au): features of alloys and sample characteristics

Post updated: Jun 6, 2020

750 gold is the leader in sales worldwide. What is the reason for such popularity? Let's try to figure it out.

Gold is the oldest noble metal discovered by man and used in ancient times. Various products of fabulous value and no less impressive beauty are discovered at the sites of excavations of ancient pyramids and burials, because the yellow metal was highly valued even then.

In our times, it has not lost its value and is used in jewelry and banking.

Now it is produced in the form of ingots for bank storage, plates for processing various surfaces and in the form of decorative wire.

After a cycle of purifying gold from various impurities, it receives the highest percentage of purity, while becoming very elastic and fragile, which makes it impossible to use it as jewelry.

To enhance strength and hardness, admixtures of other precious (and not so precious) metals are used. In precious metals, the hallmark determines the amount of pure metal per kilogram of alloy.

Areas of application

This 750 grade gold alloy is used primarily for the production of jewelry. The most popular of these are wedding rings. Such rings turn out to be very elegant and will please their owner for a long time.

In addition, when certain metals are added to the alloy, 750 gold may change its color. So, by adding 8.3% silver and 16.2% copper, you can get a pink tint. Using 4% silver and 20.5% copper in the alloy will result in a red color. And thus, by varying the content ratio of silver, copper, rhodium and palladium, you can obtain different colors and shades. In addition to pink and red, the following metal colors are most often obtained:

• Rich yellow;
• Green;
• Light green;
• Black;
• Blue;
• Violet;
• White.

This alloy can also be easily used for the production of other jewelry. For example, it behaves well when casting chain links. However, such jewelry must be carefully looked after and storage rules must be followed.

Reasons for oxidation of 750 gold

750 gold is almost indestructible. It does not darken or lose its appearance when reacting with various reagents. Acids and alkalis also have no effect on the material. However, the substance “royal vodka” can be isolated. This alloy is quite easy to dissolve in it.

However, because of this, you should not assume that 750 sample is invulnerable. An additional 25% may include low-quality and noble metals. Therefore, with some alloys the following changes may occur:

• Oxidation in open air;
• The appearance of plaque as a result of a reaction with chemicals;
• Darkening of some parts of the product upon contact with water.

But still, due to 75% pure gold in the alloy, these reactions occur much slower than, for example, 585 or 350 samples of gold. And remember that these changes occur only with low-quality alloys. If high-quality metals were used in the alloy, then such a sample is absolutely not susceptible to oxidation.

Uses of gold

According to historical information, gold is the pioneer metal with which humanity interacted. Acquaintance with him took place 2-3 thousand years ago, as evidenced by the jewelry found at the excavations. There are also references to this precious metal in the Iliad and the Bible. Gold also aroused great curiosity among alchemists, who often sought ways to transform metals into precious metals, which were credited with great power.

In the modern world, gold has several functions:

• in commodity production it performs the function of money;
• in art it is used for jewelry work;
• in medicine it is used as components of some drugs;
• also used in the chemical industry and electrical equipment.

Cleaning 750 gold items

In order for products marked 750 to serve for a long time and please with their appearance, they must be properly cared for. Be sure to store your jewelry in a special box or case. It is advisable to wipe and polish the product with a suede cloth every day. You can also use flannel.

The biggest enemy is chlorine. Therefore, it is better to remove jewelry before cleaning the house or visiting the pool. Sweat can also damage your appearance, so before going to the gym you should put your jewelry in a case. Also, do not forget about the adverse effects of mercury on the product.

Even some cosmetics can affect decoration. Therefore, you should avoid touching the product.

Another hostile environment is iodine solution. You can remove iodine stains with hyposulfite. The decoration is immersed in the solution for 20 minutes, after which it is washed and rubbed with a cloth.

Goya paste will help you give your decoration its former shine. Apply a small amount to a woolen cloth and wipe the product thoroughly. Onion juice may also help. Place the jewelry in it for 2 hours, then rinse and polish with a soft cloth.

Sometimes dark spots appear on jewelry. A solution of soap and ammonia will help remove them. The product should be kept in the solution for about 15 minutes, and then rinsed and dried. All these methods can help you keep your jewelry in excellent condition for many years.

World testing standards

Currently, there are three types of standardization of gold metal - spool, metric and carat.

The spool system is already outdated and is no longer used. Two of the above remain. Metric is used mostly in the CIS countries and Europe, and carat is used in North America. Therefore, sometimes in stores you can find carat stamps on jewelry.

All carat standardization is calculated up to 24 carats, which corresponds to a purity of 999. If you do not take into account the low carat standards such as 9 and 12, as well as the highest 23 and 24, then 14, 18 and 21 will remain. These last three will make the figure 750 clear. American dimension:

• 14 carats corresponds to our 583 hallmark;
• 18 carat - gold purity 750;
• 21 carats is already the 875th purity of gold.

When you see such numbers, you shouldn’t be scared: just translate it into a coordinate system convenient for you and everything will work out by itself. The only thing is that silver or some other metal is coated with gold plating and also has a mark of 18 . This must be confirmed by the seller. And the ring itself with gold plating 750 is no different from the real thing, only maybe over time the gold plating will begin to wear off.

How to distinguish yourself from a fake

The first thing you need to pay attention to when buying gold jewelry is the stamp. It must indicate the sample of the product. The brand itself should resemble a spatula. Moreover, depending on the country of manufacture, there may be different drawings next to the sample, for example, for Russian manufacturers it is a girl in a kokoshnik.

To determine the sample at home, you can use iodine or a bite, but there is a possibility of seriously damaging the appearance of the jewelry. The most popular method at the moment is using a touchstone. This method does not harm the decoration and allows you to accurately determine the sample. It is necessary to draw a line with the product along the surface of the slate. A test strip is drawn nearby with a special needle. The scratches are then exposed to a chemical solution. At 750 sample, the color of the strips will be identical.

The sample can also be determined using a regular glass of water and a scale. With this method, the density of the product is measured. That is, the product is simply weighed. Then a glass of water with the decoration placed in it is weighed. In this case, the decoration should not touch the walls of the glass. The first value is divided by the second, so we get the density of the product. Sample 750 should have a density of approximately 15.5 g/cm3. White gold can be considered an exception; its density due to palladium can reach up to 16.5 g/cm3.

White gold

18k white gold is an alloy of gold with nickel or palladium. Sometimes platinum may be present. The white gold alloy itself has a rather dull shine. To make it brighter, a thin rhodium plating is used, which, if the jewelry is worn frequently, must be renewed quite regularly.

The typical work technique used when making jewelry is granulation. Tiny granules are welded to a very thin gold plate, and with their help, a pattern is created on the product. This type of technology dates back a long time, as evidenced by historical and scientific excavations.

Currently, many lovers of precious jewelry have heard of such famous jewelry houses as BULGARI, DIMIANI, which use the granulation technique.

When purchasing gold products, you should pay attention not only to the price, but also to the availability of the necessary certificates and passports. It is worth purchasing products from trusted and well-known manufacturers in specialized stores.

Cost per gram

It is difficult to determine the price per gram with an accuracy of a penny, since the market price of the precious metal is fickle. In addition, the price of 750 gold does not always directly depend on the exchange price. In the case of this sample, many factors influence:

1. The indicator 750 is very close to 999, which means its price will be approximately twice as high as 583.
2. The cost of the finished product includes labor. That is, it all depends on the complexity of the order.
3. The price will be an order of magnitude higher if the manufacturer is a well-known brand.
4. Well, of course, the weight of gold and the presence of precious stones greatly increase its value.

If, based on such principles, you have to sell jewelry, be prepared to reduce the real price several times. Pawnshops usually do not give more than 30% of the real value. The seller has to negotiate individually with private individuals. In any case, you always lose on sale.

How can you save your capital using gold?

Many people know that gold is a very liquid metal. Often people invest their savings in gold to save money over time. However, you need to remember: this type of investment makes sense only when buying bank bullion, and in no case will save money if you buy jewelry. At a bank you pay for metal, while at a jewelry store you pay for the work of a craftsman. If you need to sell the product, you will receive for it, at best, a third of its value - the price of scrap gold. Thus, investing in jewelry is a loss-making endeavor.

Main differences from silver and platinum

When comparing different materials, it just seems impossible to tell the difference. In fact, it is quite possible to independently determine the type of product. No magic ritual is used for this, and you don’t have to rely on signs either. It is enough to study the signs:

• shape of the hallmark: on silver items you can see the likeness of a barrel, with a hallmark in it, on platinum jewelry - an octagon, on jewelry made from Au metal - a rectangle;
• samples of silver (800, 830, 875, 925, 960) and platinum (850, 900, 950) are much higher, while the likelihood of repetitions is excluded, which means that there cannot be two identical silver or platinum products with the same hallmark - they are always different;
• gold items (yellow) coated with rhodium gradually darken as the protective layer wears off, platinum jewelry does not have this feature, and silver jewelry even oxidizes over time.

White gold, platinum and silver - differences

The importance of caring for, cleaning and carefully storing fine white metal at home

Basic recommendations:

• You should not wear jewelry during physical work;
• they need to be removed before going to the sauna;
• jewelry should not come into contact with chemicals (detergents and cosmetics);
• For storage, a box with compartments and a soft covering inside is provided.

You should also periodically clean the products, for which the following products are used: “Flyurin”, “Talisman”. Mellerud paste is used for polishing, and special devices are used for jewelry with stones.

What is 750 sample?

It is well known that pure gold without impurities is used only in the production of bank bullion, which is used as an investment instrument. The jewelry industry uses the glory of gold and other metals. The most common impurities are copper, nickel, palladium, zinc, silver, and manganese. They are called alloy and perform the function of improving the strength, wear resistance and durability of the metal. In order to indicate the amount of ligature in the product, a sampling system was introduced. For example, a sample of 750 means that one kilogram of the alloy contains 750 grams of pure gold and 250 grams of impurities.

This system is called metric. It has been approved throughout the Russian Federation, which is reflected in current laws and government regulations. Additionally, there is a list of approved alloys that are allowed to be used in the jewelry industry. The metric system is not widely used abroad, but the carat system is in use. It is based on 24 parts of metal. Hallmark 750 is equivalent to 18 carats.

What are the differences between samples 585 and 750?

When purchasing jewelry, buyers often make a choice based on the ratio of price and quality. Connoisseurs who value the status and awareness of an expensive product in stock choose 750 sample. Buyers who prefer more economical, but at the same time high-quality material, purchase items marked 585.

Gold is an amorphous material in its structure. Daily wear of jewelry leads to the rapid appearance of scratches and deformation. Copper, nickel, platinum, silver as alloying components improve the strength characteristics of the alloy.

The brand in question contains 25% impurities. Such jewelry will not withstand constant wear; its appearance will deteriorate under the influence of external conditions. Products marked above 585 are more suitable for one-time exits and special events.

The 585 yellow metal contains a larger amount of alloying components. Products made from this material are more resistant to mechanical stress, resist corrosion well, and have high strength. Jewelry made from low-quality raw materials can be worn every day without any fear for its condition.

From raw materials 585 brands create jewelry that is simple in form, without additional elements. This brand is not used for premium goods, as it does not lend itself to complex decorative work due to its high strength.

A distinctive feature of high-quality raw materials is their flexibility in processing and polishing. This alloy allows you to create complex, elegant compositions with ornate weaves and openwork patterns. Precious jewelry in which noble raw materials are coated with enamel is currently popular.

Jeweler's comment

Molokanov N.M.

Jeweler, 26 years of experience in jewelry production.

In addition to the main signs of the quality of jewelry (the sound of falling on glass, color, weight), you can focus on price. This is an indirect factor and cannot be taken as the main one. However, most often low-quality products or counterfeits are sold at reduced prices.

Product quality

The inert metal aurum does not react with oxygen, and, therefore, the air does not oxidize it. It would seem that all gold-containing alloys, where 750 standard is indicated, should not darken from reagents. Just as they should not be afraid of acids and alkalis, except perhaps from contact with aqua regia. But we must not forget about ligature impurities. Some of them oxidize in air or when exposed to a humid environment. This leads to the formation of a dark coating, but this happens much more slowly than on their low-grade counterparts. Do not also forget that high-quality products can be easily damaged. If handled carelessly, scratches may appear on the surface. For this reason, they are not suitable for everyday wear.