How is sapphire formed?

Many people like sapphire ornaments, but they don't know much about how sapphire is formed. The following is the formation process and reason of the sapphire I made for you. I hope it works for you.

The formation of Sapphire The English name of sapphire is sapphire, which comes from the Latin Spphins, meaning blue; It belongs to corundum group minerals and has a tripartite crystal system. Gemological circles call all kinds of gem-grade corundum except ruby sapphire. Sapphire and ruby, emerald, golden water, bodhi tourmaline and tanzanite all belong to colored gems.

Because corundum contains trace elements such as iron (Fe) and titanium (Ti), it appears blue, sky blue and light blue, among which bright sky blue is the best.

The mineral name of sapphire is corundum, which belongs to corundum family. In fact, the gem-grade corundum in nature is called sapphire except red, and other colors such as blue, light blue, green, yellow, gray and colorless are all called sapphire. The chemical composition (AL2O3) of sapphire is mainly iron, titanium and coloring.

Sapphire is composed of alumina, which is blue because it contains trace elements of titanium (Ti4+) or iron (Fe2+). It belongs to the tripartite crystal system. Crystal shape is often cylindrical, short column, plate and so on. The geometric shape is mostly granular or dense block. Transparent to translucent, glass luster. Refractive index 1.76- 1.77, birefringence of 0.008, strong dichroism. Not an isotropic body. Sometimes it has a special optical effect-starlight effect. The hardness is 9 and the density is 3.95-4. 1g/cm3. No cleavage, cleavage development. When there are three groups of inclusions parallel to the bottom in the arc cutting and grinding, it is called "starlight sapphire", which can produce beautiful starlight.

The characteristics of sapphire The biggest characteristic of sapphire is uneven color, and flat bands and growth lines with different shades arranged in parallel hexagonal columns can be seen. Poly-sheet has the development of bimorph, and the bimorph pattern of louver is common. Cleavage often cleaves along double crystal planes. Dichroism is strong. In addition to the above characteristics, sapphires all over the world have their own characteristics due to different places of origin.

Sapphire and ruby are sister gems. Both of them belong to corundum minerals, which are the hardest natural minerals except diamonds, and their basic chemical composition is alumina. In addition to the starlight effect, only translucent or transparent corundum with bright colors can be called gems. The red corundum containing chromium is red, so it is called ruby. Blue sapphire is because it contains trace amounts of titanium and iron. In fact, in addition to red corundum gems, corundum of various colors is collectively called sapphire in business. So sapphire not only refers to blue corundum, but also a complete blue series, such as yellow, pink, orange and purple, as the sunset glow of fireworks. These colored sapphires are collectively called colored sapphires.

The selection method of sapphire is 1. The color of sapphire is an indicator of its value. A deep sapphire may cost HK$ 100 per card, but a good cornflower sapphire costs HK$ 10,000 per card. In America and Europe, people prefer dark sapphires. In Hong Kong, consumers like medium dark blue, which is a kind of sapphire with higher price. Put the sapphire out of one arm and carefully observe whether it is blue or black. If it is blue, then your choice is not far away.

2. Look at gems under natural sunlight and artificial light. Gemstones will look brighter in strong light, but they will be darker in general sunlight.

3. See if the color is even. Cracks will affect the beauty and durability of gems. If the feather extends to the surface of the stone, a sudden impact (such as rubbing a sparrow) will break the gem.

4. Don't forget to observe the cutting and proportion of gems.

Like rubies, be careful of imitations and fakes.

Sapphire and similar minerals can be correctly distinguished by their respective mineral crystal characteristics. Gem-grade blue cone ore is only produced in the United States, and the output is very small. Although its color is similar to sapphire, its hardness is small, and its Mohs hardness is only 6-6.5, so it can be distinguished from sapphire by hardness alone. Natural sapphire has birefringence, while spinel is single refraction. If there is a red flash in the sapphire, it can be concluded that the sapphire is spinel or zoisite. Sapphire's high hardness, high density and high refractive index can be distinguished from tourmaline, cordierite and zoisite.

The Economic Value of Sapphire Both natural ruby and sapphire have some defects in different procedures. The primary factor of economic evaluation is color, and spring is important, transparent and pure. As far as the value of ruby is concerned, pigeon blood red is the best, followed by rose red and pink. Generally speaking, Burmese rubies are bright red, and their value is higher than that of deep red rubies made in Thailand.

The best sapphire is cornflower blue from Kashmir, India, followed by dark blue, light blue, green and yellow. The value of high-quality sapphires is comparable to that of rubies. Indigo blue, transparent sapphire, granularity 6X8mm, value $ 1600 /ct. Ruby and sapphire particles produced in nature are small, and the value of gems increases by the square of weight. However, if the weight of the gemstone exceeds 5 carats, it needs to be negotiated separately according to the quality of the gemstone.

Factors affecting the value of precious stones:

① Quality: The quality of a gem determines its price.

2 beauty: beauty is the most basic condition of gemstones. Some colors are gorgeous, pure, transparent and brilliant, such as five-color transparent diamonds. Some show special physical and optical effects such as starlight, cat's eye, discoloration and discoloration, such as starlight sapphire, opal, high-grade opal and stone change.

(3) Durability: As a hereditary thing, high-grade gems will be able to keep their beautiful colors forever and withstand the changes of light, cold, heat and humidity. Generally speaking, gems must be minerals with hardness greater than 7, while sapphires have hardness of 9.

4 Scarcity: Things are scarce.

Sapphire processing Under high temperature treatment, Australian sapphires that are too dark or dark blue will become lighter. The white corundum in Sri Lanka can be blue, and the light yellow treasure can also be changed into deeper and warmer yellow. In short, there are five applications:

A: Reduce the blue color of dark sapphire (under oxidizing conditions).

B: deepen the blue color of sapphire (under reduction condition)

C: removing filiform inclusions and undeveloped starlight from sapphire (rapidly cooling after heating)

D: generate starlight (slowly cool after heating)

E: Light yellow and yellow-green corundum are heated under oxidizing conditions to become orange to golden sapphire.

Unfortunately, this manual processing method is not easy to identify. However, high temperature treatment will make the gemstone brittle, which is more likely to cause cracks inside the gemstone.

Many corundum on the market are treated at high temperature. Because this method imitates the natural process to imitate the gem, the color of the gem will not fade after changing, which is acceptable in the industry, but honest businessmen will definitely make a statement to their customers.

High temperature treatment will make the cracks more obvious, so this artificial treatment uses clear (less inclusions) but poor color quality gems.

Most sapphires produced in Shandong (Changle) mining area have been decolorized. In decolorization treatment, the raw materials are generally good in texture, dark in color and mature in decolorization technology. Some sapphires sold in the market are decolored. This practice is acceptable in the industry, and honest people will definitely give customers a statement.

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