Yikela photography

A photographer from China once walked into the Wa region of Myanmar and recorded the making process of a gem with his own experience. It has strong fortifications and the miners work very hard. Usually, they get a carat of gems for every 500 tons of ore mined. Photographers call it "blood diamond", which means that every gem here is bought by miners with their own blood, sweat and even life.

This is a precious ruby.

After the gem

Ruby is as bright as a flame, and its English name Ruby comes from Latin ruber. Its original meaning is red. It symbolizes passion, passion and beautiful and loyal love. It is called "the stone of love". Now, the 40th anniversary of marriage is also called "ruby wedding" in western countries to praise eternal love.

From the mineralogical point of view, ruby is actually corundum, and its main component is alumina. Corundum is the most durable crystalline alumina known at present. Sometimes it contains trace amounts of iron, titanium or chromium. Its hardness is very high, second only to diamond. 18 12 years, German mineralogist Moss first put forward a standard to express mineral hardness, that is, Mohs hardness. The hardness of the following 10 minerals is expressed by 1- 10: talc, gypsum, calcite, fluorite, apatite, orthoclase, timely, topaz, corundum and corundum. The hardness values here are not absolute hardness values, but expressed in the order of hardness. It can be seen from Mohs hardness value that the hardness of diamond is 10, followed by corundum, which is 9. Diamonds can only be painted with other words on the surface. Because of this, some people look at rubies in this way: if diamonds are the "king of gems", then rubies are the "queen of gems".

In the past, some miners mistakenly thought that if a dull ruby was buried underground, it would eventually turn bright red. Ruby is the most mature member of the corundum family. Although their understanding is incorrect, it is a fact that the redder a ruby is, the higher its value is. Blood ruby is the most precious, commonly known as "pigeon blood red". Because its gems are more precious than diamonds. If it exceeds 2 carats, it is very precious. The world's largest "pigeon blood red" is only 55 carats. At an auction in Geneva, Switzerland, a 15.97 carat "pigeon blood red" gem from Myanmar was sold at a price of $2.27 million per carat. This is the highest unit price of ruby ever.

Modern scientific research has found that rubies are not as mature and rosy as before. This is because corundum is mixed with other elements. Pure corundum is colorless, but it will contain a small amount of chromium, iron, titanium, manganese and vanadium, which will change the color of corundum: chromium-containing, mainly chromium oxide, will make corundum appear red when the content exceeds 1%, that is, ruby; Corundum containing iron and titanium is blue, corundum containing nickel is yellow and corundum containing manganese is rose.

Ruby is bright red because it contains chromium. To some extent, the higher the chromium content in corundum, the brighter the color.

Chromium makes gems colorful.

Speaking of chromium, we are no strangers, because stainless steel kitchen knives, auto parts and other utensils we use every day all contain this substance, which is called the hardest metal. Its surface has silver luster, high melting point, hard texture, wear resistance, high temperature resistance and corrosion resistance; Stainless steel made of it has not only high strength, but also high heat resistance and is not easy to rust, so it is widely used in metallurgy, chemical industry and other industries.

Interestingly, the English name of chromium comes from Greek, which means "color", because many chromium compounds have different colors. For example, chromium trioxide is dark green, potassium dichromate is orange red, ammonium dichromate is orange, and sodium chromate is yellow. Almost every chromium compound has its own unique color. Chromium, like a chameleon, makes the world of chemicals colorful.

Why can chromium turn colorless corundum into bright red?

Before explaining this phenomenon, we need to understand two questions: first, what is the color of the gem? The color of a gem is actually the result of its selective absorption of visible light with different wavelengths. When white light shines on a gem, it will absorb part of the light and reflect or transmit another part. The color observed by our eyes is actually the color of reflected light or transmitted light; The color of the absorbed light disappears. The second term is mineral isomorphism. As the name implies, different substances can show the same appearance. Strictly speaking, it means that a particle (atom, ion or molecule) in the crystal structure of a mineral is replaced by other similar particles, but the structural form of the mineral remains unchanged. Whether this phenomenon can occur depends not only on the properties of the particles themselves, but also on physical conditions such as external temperature and pressure.