The density of gold is one of the unique physical characteristics of this metal. Since it is soft, for use in practice, other metals are added to it to improve technological properties.
In jewelry, as we know, alloys of precious metals are used in different proportions. The pure noble metal content in the alloy is measured in thousandths: the 585th test is an alloy with a pure gold content of 585 parts out of 1000. The corresponding indicator is affixed to the product. Accordingly, with the addition of other metals, the density of gold, that is, its alloy, changes. On the basis of this indicator, in the places where gold products are received, their authenticity and compliance with the declared sample are determined.
Gold characteristics
Precious gold is a heavy metal. Its density in its pure form is 19 621 kg / m³. To perceive a dry fact as bright as possible, imagine a small ball of pure metal with a diameter of 46 mm. Its mass will be equal to 1 kilogram.
High density of gold is also used in its mining: it is thanks to it that nuggets and sand can be weeded out from rocks by washing.
The density of gold in its pure form (the one that is considered to be the 999.99th breakdown) is 19.3 g / cm 3 . Native, it has a slightly lower density: 18-18.5 g / cm 3 . In alloys of different samples, this indicator is different. We will talk about them later.
Density of Gold Alloys
As we know from the school year, the density of a material is a physical property, defined as the mass of a taken unit of volume. It is measured through the ratio of body weight and its size.
To obtain alloys suitable for use in jewelry production, gold is mixed with copper, silver, nickel, platinum, palladium and other metals, both noble and not. Let us turn to the data on the density of gold alloys of different samples.
The most popular, affordable and excellent for working with it is the 585th test. The density of gold of the 585th test is 12.5-14 g / cm 3 . The same framework is determined by the 583rd test (Soviet model).
For coin samples, the 900th and 917th, the indicators are equal, respectively, 17.10-17.24 g / cm 3 and 17.34-17.83 g / cm 3 .
Also a frequently encountered sample in jewelry, the 750th has a density of 14.5-17.5 g / cm 3 .
The density of base gold, the 375th test, - 11.54-11.56 g / cm 3 .
And finally, remember another precious metal - silver. It is much lighter than gold, and the density of silver alloys is also lower.
So, the density of the most common alloy of the 925th test in products is 10.36 g / cm 3 . The second most used, 875th sample, - 10.28 g / cm 3 .
The density of gold and silver is an important indicator that helps to determine the content of pure noble metal in the alloy using various methods. We will talk about one of them, available later.
Hydrostatic method: determine the precious alloy sample
In institutions specializing in the reception of gold products, many different methods are used to determine and confirm the sample of gold brought. Based on the knowledge that gold is a heavy metal with a high density, the hydrostatic method was introduced.
It is based on determining the difference in weight when measuring indicators in the open air, under ordinary conditions, and in a liquid with a certain density.
We will make a reservation right away: this method of checking gold is suitable only for integral products, without stones and other inserts from other materials. It is also impossible to obtain adequate data on hollow products, consisting of many moving parts.
To carry out hydrostatic weighing of a gold product, you will need a jewelry scale, a measuring cup (or any other transparent), fishing line or a thin thread. Distilled water is usually used as a liquid of known density. First, the gold product is weighed in the usual way, the data is recorded. Then a glass of water is placed on the scales, filled with more than half, the readings of the scales are reset (the balance should have the function of zeroing the tare weight). Our gold product, suspended on a fishing line, is completely immersed in water, without touching the bottom and walls of the glass. Weight data is also recorded.
It is better to use a hydrostatic calculator for density analysis, since manual calculation will take much longer and not so accurate.
conclusions
So, in our article, we examined the density of gold - a precious metal that each of us in life has encountered and will still encounter. To summarize the data presented as follows: the density of the most popular gold sample, 585th, is 12.5-14 g / cm 3 , for other alloys it is lower or higher, respectively.
According to the density of the gold alloy, you can determine the sample, which is an indicator of the content of pure gold in the alloy. These methods are used in institutions that accept gold.
We hope our article was informative and presented you with some fascinating minutes. Let only real high-grade gold be in your casket!