Myths and legends

What does artificially grown sapphire mean?

There are different ways to grow crystals, each with its own benefits. The choice of method depends on many factors, including the required crystal characteristics, availability of equipment and raw materials, and the cost-effectiveness of the process.

Artificial crystal growth

Artificial crystal growth is a process in which crystals are formed not under natural conditions, but under specially created laboratory conditions for this purpose. This allows you to control the process and obtain crystals of the desired size and shape. An artificial sapphire grown in this way has all the properties of a natural one, but at the same time it is easier and cheaper to produce. Our company “Rostoks-N” is engaged in the production and processing of artificial sapphire for the needs of science and technology. We grow single crystals using three melt crystallization methods: Stepanov (EFG), Kyropoulos and Czochralski. We will tell you more about them in our article.

Production of synthetic sapphire by the Stepanov method (EFG)

Since 1938, this method has been used to produce many profiles of crystals of metals, semiconductors and dielectrics of constant cross-section, as well as products of complex shapes. Due to the fact that the desired crystal shape is achieved directly during the crystallization process, the costs of additional processing are reduced to a minimum, which ultimately speeds up and reduces the cost of the artificial sapphire production process. As the crystal grows, the melt flows from the crucible through the capillary channels of a special shaper to its working surface. It is these edges that define the contour of a thin layer of melt (meniscus), which is located between the working end of the shaper and the interphase boundary. What the cross-section of the drawn crystal will be depends on the geometry of the edges. When optimal thermal field conditions are reached, the seed crystal is in contact with the liquid meniscus. The melt, entering through the capillary channel onto the surface of the shaper, crystallizes and forms the profile of a growing crystal, for example, a pipe, plate, etc.

  • high growing speed;
  • low cost;
  • crystal length up to 700 mm.

Production of synthetic sapphire using the Kyropoulos method

  1. The seed is mounted in a water-cooled crystal holder and is in contact with the melt located in the crucible.
  2. The calculated parameters for reducing the temperature and drawing speed lead to the growth of a crystal in the form of a hemisphere directly in the crucible.
  3. As the crystal grows, it expands to the walls of the crucible, after which, together with the crystal holder, it rises several millimeters. Then the crystal grows again until it grows again to the walls of the crucible, then rises, etc.
  4. To reduce internal stresses, the crystal is annealed for a long time directly in the growth installation after the growth process is completed.
  5. In the production process using the Kyropoulos method, the diameter of single crystals can be more than 300 cm. In fact, only the dimensions of the crucible set the final limit. Advantages of the method:
  • high purity of crystals (no worse than 99,995), which allows them to be used both in laser optics and microelectronics;
  • possibility of producing crystals of large diameters (more than 300 mm).

In Fig. a diagram of the installation for growing crystals is presented; in Fig. b – stages of growth.

Growing single crystals using the Czochralski method

The Czochralski method is a classic method for producing artificial sapphire. It is based on one of the technologies for producing artificial single crystals – growing single crystals from a melt. This method requires certain technological equipment, constant control of temperature and other parameters of the growing process. The resulting crystals are of high quality, ideal for use in electronics and optics.

The creation of the method dates back to 1916, when Professor Jan Czochralski accidentally dipped the nib of his pen into a crucible containing molten metal. Instantly pulling out the pen, he discovered a crystallized ball.

Currently, not only crystals of metals and semiconductors are grown using the Czochralski method, but also a number of refractory oxides: sapphires, rubies, some varieties of corundum, garnets, etc.

One of the main advantages of the method is the production of crystals with a low level of internal defects.

A single crystal is grown using the Czochralski method by gradually drawing it out of the melt. In this case, the temperature of the melt is either constant or varies according to a certain law. Induction or resistive heating is used.

A modern installation for growing artificial sapphire consists of the following elements:

  • tungsten or molybdenum crucible;
  • thermal insulation;
  • device for creating a vacuum or inert gas;
  • device for rotating and pulling the crystal;
  • a mechanical, optical or electronic system to control the process.
  • the possibility of introducing alloying additives and obtaining colored crystals;
  • obtaining crystals with a low level of internal defects.

Currently, our company produces crystals using the Czochralski method with a diameter of up to 50 mm and a length of up to 200 mm; Kyropoulos weighing up to 100 kg (with a diameter of up to 300 mm), and using the Stepanov method – crystals in the form of ribbons, tubes and rods up to 700 mm long. Depending on your needs, we can offer crystals produced in different ways. For additional advice, you can contact our experts: call +7 (496) 527-35-91 or email us info @ rostox – n. ru.

Sapphire from the Zlatograd company is not an imitation, but a real sapphire grown in a human-controlled environment. This is no different from the way pearls are grown. Once the necessary combination of chemical and environmental factors is replicated in nature, the crystals grow over the course of a year, the length of which varies depending on the gemstone. In the network of jewelry workshops Zlatograd you can order and buy artificial sapphire in St. Petersburg of any shape and size.

Why buy synthetic sapphire?
Identical physical, optical and chemical properties. Sapphire has almost the same atomic and optical properties as natural sapphire. Unless you are a certified gemologist with a powerful microscope, you will not be able to tell the difference between created gems and mined ones. Lab-grown sapphires can even look better than their natural counterparts! In a laboratory setting, computers control the temperature while foreign materials found in the soil are removed from the original chemicals.

Lab-created sapphire is less rare than natural sapphire. As a result, they may be more suitable for conservative budgets. The price difference between Chatham-created stones and natural gemstones of similar quality is noticeable, sometimes up to $100 per carat, as is the case with colored diamonds. Synthetic sapphire is an excellent choice for those looking for an affordable gemstone without sacrificing the quality or aesthetics of their jewelry.

Buy artificial sapphire in St. Petersburg! Together with our designers, create a unique handmade piece of jewelry. Wide selection, excellent prices in the Zlatograd jewelry chain!

Prices for cut artificial sapphires:

Circle cut – from 300 rubles.

size (mm) price for 1 piece (rub)
1,00 300
1,25 300
1,50 300
1,75 300
2,00 300
2,25 300
2,50 300
2,75 300
3,00 300
3,50 300
4,00 300
4,50 350
5,00 450
5,50 500
6,00 550
7,00 700
8,00 900
9,00 1200
10,00 1600

Square cut – from 300 rubles.

size (mm) price for 1 piece (rub)
2,0 × 2,0 300
2,5 × 2,5 300
3,0 × 3,0 300
3,5 × 3,5 300
4,0 × 4,0 375
5,0 × 5,0 625
6,0 × 6,0 875
7,0 × 7,0 1250
8,0 × 8,0 1625
9,0 × 9,0 2000
10,0 × 10,0 2500

Oval cut – from 300 rubles.

size (mm) price for 1 piece (rub)
5,0 × 2,5 375
5,0 × 3,0 375
6,0 × 4,0 450
7,0 × 5,0 725
8,0 × 6,0 900
9,0 × 7,0 1175
10,0 × 8,0 1450

Pear cut – from 300 rubles.

size (mm) price for 1 piece (rub)
5,0 × 3,0 375
6,0 × 4,0 400
7,0 × 5,0 600
8,0 × 6,0 800
9,0 × 6,0 1000
9,0 × 7,0 1300
10,0 × 7,0 1600

Marquise cut – from 300 rubles.

size (mm) price for 1 piece (rub)
4,0 × 2,0 300
5,0 × 2,5 300
6,0 × 3,0 450
7,0 × 3,5 550
8,0 × 4,0 725
10,0 × 5,0 1075
other sizes by agreement

Octagon cut – from 250 rubles.

size (mm) price for 1 piece (rub)
5,0 × 3,0 300
6,0 × 3,0 375
6,0 × 4,0 375
7,0 × 5,0 375
8,0 × 6,0 700
8,0 × 4,0 1000
9,0 × 7,0 1300
10,0 × 8,0 1600
Other sizes by agreement

Baguette cut – from 300 rubles.

size (mm) price for 1 piece (rub)
4,0 × 2,0 300
5,0 × 2,5 300
6,0 × 3,0 375
6,0 × 4,0 375
7,0 × 5,0 500
8,0 × 6,0 700
8,0 × 4,0 1000
9,0 × 7,0 1300
10,0 × 8,0 1600
other sizes by agreement

Heart cut – from 300 rub.

size (mm) price for 1 piece (rub)
3,0 × 3,0 625
4,0 × 4,0 625
5,0 × 5,0 750
6,0 × 6,0 1000
7,0 × 7,0 1250
8,0 × 8,0 1625
9,0 × 9,0 2000
10,0 × 10,0 2500

Trillion cut – from 300 rubles.

size (mm) price for 1 piece (rub)
3,0 × 3,0 625
4,0 × 4,0 625
5,0 × 5,0 750
6,0 × 6,0 1000
7,0 × 7,0 1250
8,0 × 8,0 1625
9,0 × 9,0 2000
10,0 × 10,0 2500
other sizes by agreement

All prices do not include the cost of fastening!
The cost of setting is 10-20% of the price of the stone, but not lower than that established in the price list.
Please note that the color of the natural stones presented in the workshop differs depending on the size: in larger sizes the stone is darker, in smaller sizes it is lighter.

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  • City: Saint-Petersburg
  • zlatogradgold@yandex.ru

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