What are the colors of sapphires?

Since ancient times, people have loved to decorate themselves. At first, there were simple wreaths and necklaces of bright colors, then seashells and beautiful minerals. Later, people learned to process natural, often nondescript crystals so that they became genuine treasures. This article will focus on sapphires.

Sapphire is one of the most beautiful and expensive natural gemstones, and it has been so almost always, since ancient times, when people learned to mine and process these natural crystals.

Sapphire, like its cousin ruby, belongs to corundum - a mineral based on aluminum oxide with various impurities, which color the crystals in different colors. Distinguish between classic and fancy sapphires. The first group is blue crystals of various shades. Well, the second includes all the other corundums, except for the deep red ones - these are rubies.

The main parameters for evaluating the color of precious stones, including sapphires, are hue, color saturation and lightness. There is no shade standard for fancy sapphires due to the variety of their colors. And for classic blue crystals, the best is the cornflower blue tone - the color of sapphires mined in Kashmir.

Sapphires are considered to be powerful talismans.Many sources write that they help from the evil eye, damage and deception, contribute to the acquisition of wisdom and tranquility. Mariners and travelers loved to wear it, especially they loved asteria stones (star sapphires).

The color of the stone depends on its composition. Even a small amount of impurities can drastically change the color and purity of a sapphire.

Color saturation is largely dependent on the amount and percentage of impurities. According to a simplified scheme, blue sapphires are divided into bright, medium and light stones. Professionals use 5 degrees of lightness and 3 categories of saturation when evaluating crystals.

Colored sapphires come in a wide variety of colors, excluding, as mentioned above, the deep red color.

The most expensive are deep blue gems, followed by pinkish-orange stones (“padparadja”, which means “lotus flower”), then pure pink crystals. Yellow transparent sapphires and blue opaque asteria (stones, on the polished surface of which the pattern of a 6- or 12-ray star is clearly visible) occupy the 4th place in terms of cost. A step below are orange, green, purple gems, as well as sapphires that have alexandrite effect - that is, they change color depending on the lighting. The cheapest are colorless stones, as well as black simple and star-shaped ones. In fact, it is not entirely correct to call black sapphires black - they are blue, just because of the high color saturation they appear dark and opaque.

Sometimes there are crystals, one part of which is colored in one color, for example, blue, and the other in another, for example, yellow. Such stones are called polychrome, or multi-colored, they are rather highly valued due to their rarity.

When choosing jewelry with any precious or semi-precious stones, ask for a certificate confirming the natural origin of the mineral. Nowadays, many precious stones are grown artificially in autoclaves. It is impossible to distinguish them from natural ones with the naked eye. But there is a significant difference in price, because natural sapphires are very, very expensive, and this already creates ample opportunities for all sorts of fraudsters. Therefore, do not forget about certificates, and in case of purchasing large stones, do not be too lazy to order an examination, because it is very easy to be deceived.

There is an easy way to test the naturalness of a stone: direct the light of an ultraviolet lamp at it. Natural crystals should turn green in this case, but synthetic ones should not.

When looking at the certificate, pay attention to the grade of the stone, for example, 1/2. The first number indicates the color of the stone (1 - blue), and the second - the quality category (depending on the clarity of the stone and the level of transparency of the crystal). There are only 4 quality categories. The first includes stones of the highest purity and transparency, in which there are practically no defects. The second includes transparent sapphires of a lower quality - with small defects or with an overly saturated color. In opaque stones of the third category, defects can be seen with the naked eye. Well, the fourth group includes turbid crystals with pronounced flaws.

Also, do not forget to see if the stone belongs to the ennobled or not. To improve the quality, most natural sapphires are thermally treated, that is, heated. This allows you to change the color of the stone, increase its transparency, etc. This treatment has no effect on the physical properties of the mineral, but unrefined natural sapphires are valued much higher than processed ones.

Look through the stone into the light, best of all natural. Microcracks can often be seen inside the crystal, which reduce the quality, and, accordingly, the price of the stone. Rate the cut of the stone. Sometimes, due to improper processing or unscrupulous grinding, the appearance of the gem seems to fade, not reflecting all its possible beauty.

The price of crystals also strongly depends on the country of their production. The most expensive stones are considered to be mined in Kashmir, Sri Lanka and Tanzania. Burmese and Thai crystals are the second. Next - mined in all other countries of the world, except Australia, as Australian sapphires are at the bottom line of the price rating of these minerals. It should be noted that the Kashmir field has already been depleted and closed. There are also several corundum deposits in the Russian Federation - on the Kola Peninsula (blue, greenish, cornflower blue) and in the Urals (gray-blue).

The properties of sapphire are described below.