What does a synthetic ruby look like?
A stone of passion and frantic energy. Perhaps it’s all about the color, but this is one mineral that you can’t take your eyes off. It is possible that this is precisely why the royals of many kingdoms turned their gaze to the “scarlet flower” of the bowels of the earth. 
Majestic rubies adorned the royal regalia of many states. How much is the “Polish Eagle” hairpin, which is kept in the Louvre, worth? Or Elizabeth II’s ruby Burmese tiara? And the majestic “Monomakh’s Cap”? It is decorated with 8 large rubies on each of the plates. In the old days, rubies were called, in the European manner, yakhont. And the older our world becomes, the more attractive the stone seems to us.
Yakhontovye mines
The main deposits are considered to be India, Thailand, Vietnam, Tazania, Sri Lanka and Australia. But the most valuable are those mined in the mines of Myanmar. Imagine not just a dark red transparent ruby, but with a bluish tint – called “pigeon blood color”. Dark rubies of a noble burgundy color are found in a mine in the city of Mogou. And near the city of Mong Shu, gemstones are mined with amazing purple, blue and black colors at the core, with red ruby edges.
In India, you can come across star-shaped rubies – if you hold one up to the light, you can see a star.
Pink, like ripe raspberries, specimens can be found in Sri Lanka. And minerals that shimmer in the light are mined in Africa. To get cut, stones are most often sent to Europe, Thailand and Israel. Jewelers have a difficult job; a ruby is rarely pure, without inclusions of other materials. These inclusions are removed, the cracks are glued together, and the voids are filled with glass melt.
The price of ruby passion
Rubies are not only the brightest stones, but also one of the most expensive, surpassing even diamonds in value. If we are talking about high-quality, pure and transparent ruby, then the price can reach hundreds of thousands of dollars and more.
The most expensive example, called Sunrise, was sold at Sotheby’s for almost $30,5 million.
That is, approximately a little more than 1 million per carat! And today this is a record. The second record holder is the largest ruby - its size is 440 carats. Found quite recently in Greenland. It is still unnamed, but it is not difficult to guess that such a stone will be given a name to match. There are also cheap, low-quality rubies, these are often sold in Indian markets. Their cost is about 25 rupees per carat (that’s less than 1 dollar). A bracelet made from such stones will cost about 2000 rupees (about $30).
The magic of red stones
Fiery red stones may have been the eyes of a dragon in the past, as an ancient Eastern legend says. Fascinating, hypnotizing – if huge snakes existed, they would definitely look at the world with two ruby drops. Already 2000 years ago, people began to attribute magical properties to rubies. For example, it was believed that ruby enhances the good and bad qualities of nature: an evil and powerful person with such decoration can become an even greater tyrant, and vice versa. Ruby is still used as a talisman to protect against the evil eye, envy and slander.
The red mineral will help those who are overcome by doubts and uncertainty, and will restore harmony, peace and vitality.
It is a stone of health, prosperity, greatness and success. For Aries, such an amulet will restore mental strength and help get out of a depressive mood. This stone will give Scorpio confidence and push them to new beginnings. Gemini will be given flexibility and restraint. Ruby color will help Leos achieve their goals. But Aquarius and Virgo need to be careful with such a stone: they may not be able to withstand its power.
Synthetic ruby
The first synthetic ruby was created by the French scientist Mark Houdin back in the 19th century. Now artificial stones are produced on an industrial scale. Rubies are grown from a mineral called corundum. This ruby looks like a natural one, and the chemical composition is similar. It’s just that the product is initially transparent, and then it is painted with chrome particles.
How to choose a ruby
The price is affected by both weight (carats) and color. Shades of ruby can range from burgundy to crimson. But the standard and most expensive stone is a pure red stone (Pigeon’s Blood), which contains a lot of chromium and little iron. To understand the purity of a stone, look at it with a magnifying glass and pay attention to the structure: it should be heterogeneous, interspersed. Cracks and cloudy areas are formed due to crystalline inclusions (zircon, apatite, boehmite, rutile). A perfectly clean sample should make you wonder: is it a fake? By the way, specialized homology centers carry out professional testing and certification of precious stones: GRS, AIGS, GIA, SSEF, IGI, AGTA, EGL, HRD.
How to distinguish a fake
- Look carefully at how the stone shines and what color it is. At different angles it should change from dark to light;
- run the stone across the glass. If a reddish mark remains, the stone is most likely artificial;
- try scratching the ruby itself, for example, with a coin. Don’t be afraid, real natural stone will not be damaged;
- lower the sample into the glass: highlights should appear in it. And if you pour milk into a glass, it will turn pinkish;
- look at the cracks: are they straight and shiny? Here is a synthetic; in natural stone they are zigzag and matte;
They can also sell it for a ruby pomegranate, tourmaline, rubellite и spinel. Mineral reserves are decreasing, which means that there are more fakes and the price of rubies will only increase. So it’s a good investment.
The reasons for this were compelling. Natural rubies of high jewelry quality are rare and therefore cost tens of thousands of dollars per carat. In ancient times, only very wealthy people – monarchs, aristocrats, and nobility – could afford them.
Synthetic ruby is no less beautiful than natural ruby, but is much cheaper. But not only the price is important: synthesis technologies have made it possible to obtain crystals of the required size and weight, which made it possible to create solid-state lasers. Without synthetic rubies, modern sound recording, laser surgery and electrical engineering would not exist.
How synthesis technologies developed
The first attempts to synthesize ruby occurred in the mid-1857th century. In 1, chemist Marc Gaudin fused potassium alum with potassium chromate in a clay crucible and obtained crystals weighing about XNUMX carat. Other researchers were also able to obtain small crystals – H. Senormand, J. Ebelman, but all these attempts had no practical significance.
The breakthrough was the technique proposed by the French chemist Auguste Verneuil. He developed a technology that allows him to grow ruby crystals weighing 20-30 carats in just a couple of hours. Verneuil did not reconstruct low-quality natural stones, but synthesized rubies from a melt of barium and calcium fluorides with the addition of chromium oxide, and later from pure aluminum oxide.
Verneuil’s method turned out to be so simple and reliable that it led to the launch of mass production of synthetic rubies. It is still used almost unchanged today, although more than 100 years have passed since its invention.
However, the development of new synthesis technologies has not stopped. Later, methods appeared that made it possible to obtain large crystals with a high degree of purity and perfect structure – the Czochralski method and the zone melting method. Rubies are also synthesized using flux and hydrothermal methods, although they are not widely used.
How is a synthetic ruby born?
The Verneuil method allows you to grow crystals in much the same way as stalagmites grow in a cave. Finely ground aluminum powder, or charge, is poured in a thin stream into a special furnace, where it enters the flame of detonating gas. The flame is heated to very high temperatures – more than 2000 degrees, so the powder melts. Drops of the melt flow down onto the stand with the seed and crystallize, forming a corundum boule.
The Czochralski method is used when high-quality gem quality rubies are needed. The crystals are more uniform, with fewer gas bubbles and inclusions, and a low level of residual stress. At the same time, the Czochralski method is more expensive: its use requires expensive equipment, as well as crucibles made of refractory metals – for example, platinum.
When synthesizing rubies using the Czochralski method, the initial mixture of oxides is placed in a crucible and heated with a spiral heater. A seed rotating at a speed of 5-30 mm/hour is brought to the surface of the melt. It gradually rises, “pulling” the crystal upward. As a result, a ruby is formed with a length of 200-250 mm and a diameter of up to 20-30 cm.
Properties of synthetic ruby
Synthetic ruby is not inferior in physical and optical properties to natural ruby. It has a hardness of 9 on the Mohs scale, making it one of the hardest minerals. In terms of hardness, ruby is second only to diamond and moissanite.
Synthesis technologies make it possible to reproduce the optical properties characteristic of natural stones. Thus, using the Verneuil method, star rubies can be obtained – stones with the effect of asterism. To do this, a small amount of titanium oxide is introduced into the charge, and the resulting crystals are annealed. Thin needles of rutile are formed inside the ruby, which can be located in different ways. If they are arranged in concentric rings, they look like a multi-rayed star; if they are oriented only in one direction, they resemble a cat’s eye.
Characteristics of the stone
The cost of a natural ruby depends on 4 indicators: color, purity, weight and cut quality. The cost of synthetic depends on weight and color. This does not mean that in other characteristics it is inferior to natural stone: often the opposite is true.
Color
The color of ruby is due to the presence of chromium oxide in the composition. Depending on its concentration, as well as the presence of other impurities, rubies are:
- red;
- red-pink;
- red-brown;
- red-purple.
Chromium oxide is introduced into the charge even before the formation of the crystal begins. The concentration is determined by the shade to be obtained. For example, in dark red rubies the maximum permissible content of chromium oxide reaches 3%. A larger amount leads to clouding of the crystal and the appearance of cracks.
Synthetic rubies of a deep red color without a crimson undertone are difficult to obtain, and therefore they are valued higher.
Cleanliness
The purity of ruby, that is, the presence of foreign inclusions, depends on the chosen synthesis method. The inexpensive Verneuil method results in the formation of a large number of gas bubbles, internal cracks and other defects. They are not always noticeable without a magnifying glass, but can still spoil the impression of the decoration.
In rubies grown using the Czochralski method, inclusions are much less common. The best crystals contain no more than one particle with a size of 0.5 microns per 1 cm3.
Weight
The Verneuil method is used to synthesize small rubies. With its help, you can also obtain large crystals, but with a high level of internal stress. To synthesize rubies with a length of 20-30 cm and a diameter of up to 20 cm, the Czochralski method is used.
Cut shape
Synthetic rubies are given any desired cut:
- “oval”;
- “circle”;
- “baguette”;
- “heart”.
The shape is chosen in such a way as to highlight the best qualities of a particular specimen: rich color, shine, play. Rubies with asterism, cat’s eye or silky effects are treated with cabochons.
How to distinguish natural ruby from synthetic one
Natural rubies are distinguished from synthetic ones by inclusions. You should not think that “laboratory” stones are perfect, but natural ones are not. In fact, both have imperfections, but they are different.
Natural rubies are characterized by “featheriness” – intricately curved planes reminiscent of waves and streams of water. Gas-liquid inclusions are represented by opaque bubbles, solid ones – rutile, spinel, pyrite, zircon and other minerals.
Synthetic rubies are characterized by inclusions of rutile and other alloying additives, as well as crystals of iridium, tungsten and molybdenum – metals that are used to create crucibles for a crystallization plant. Crystals obtained by the Verneuil method are characterized by numerous gas bubbles of various shapes – elongated, flask-shaped, spherical.
Rubies synthesized by the Czochralski method are more difficult to distinguish from natural ones. An experienced specialist can notice the heterogeneity of crystal growth due to the way it is formed. But without gemological examination, only in appearance, a grown ruby is almost indistinguishable from a natural one.
Why is synthetic ruby valuable?
Synthetic ruby is the first precious stone that man managed to create. The successful experience inspired other researchers to develop methods for synthesizing crystals. Without synthetic rubies, a person would hardly have learned to synthesize sapphires, emeralds, and diamonds.
Synthetic ruby is used not only in jewelry. Large single crystals are in demand in the watch industry, weaving, and metallurgy. The main element of most modern lasers is a ruby rod, and it is made of a synthetic crystal.
A lab-grown ruby is just as beautiful as a natural one. Synthesis technologies make it possible to reproduce the full spectrum of gemstone colors, as well as obtain samples with interesting optical effects. The cost of synthetic ruby is tens of times lower than natural ruby.
