Method for identifying rubies and sapphires

Rubies and sapphires are both beautiful and transparent corundum, also known as sister gemstones. The main reason is that both are corundum minerals. The basic chemical composition of both is Al2O3, and the Mohs hardness is 9. Because both colors are It is very beautiful, and its hardness is second only to diamonds. It is rare in all parts of the world, so both of them are included in the world-recognized "Four precious stones". When choosing rubies and sapphires, how do we identify the true and false of a gem?

Ruby identification method:

Natural gemstones are “ten red and nine cracks”, and natural rubies without any cracks and cracks are extremely rare. The artificial ruby ​​has the same color, and the internal defects or crystal inclusions are small, clean, and the block is large. As a precious gemstone, natural rubies over 3 carats on the market are rare. If you encounter a large piece of ruby, you should pay attention because natural rubies are worth a thousand times more than artificial rubies. If you are negligent, you will "taking medicine."

Natural ruby ​​has a strong "dichroic", so-called dichroism, that is, there are two shades of red and orange in different directions. If there is only one color, it may be red spinel, garnet or red glass. Wait.

Red spinel is very similar to natural ruby, and the two are the most confusing, so they must be especially careful.

[Supplementary explanation ruby]

The English name for Ruby is Ruby, which is derived from the Latin Ruber, meaning red. The mineral name of ruby ​​is corundum.

The chemical composition of ruby ​​is aluminum oxide (Al2O3), which is red to pink due to the trace element chromium (Cr3+). It is a trigonal system. The crystal form is often in the form of a barrel, a short column, or a plate. The aggregates are mostly granular or dense blocks. Transparent to translucent, glass luster. The refractive index is 1.76-1.77, and the birefringence is 0.008-0.010. The dichroism is obvious and heterogeneous. Sometimes it has a special optical effect - the starlight effect, which reflects the fascinating six-shot starlight under the illumination of light, commonly known as the "six-way line." The hardness is 9, and the density is 3.95-4.10 g/cm 3 . No cleavage, crack development. Ruby emits red and dark red fluorescence under long- and short-wave ultraviolet radiation.

Among the ruby ​​reds, the most valuable is the most intense color, known as the 'pigeon blood' gem, very expensive. This bright and intense color, which can be called the deep red color, reveals the true face of the ruby. Unfortunately, most rubies are light in color and have a powdery feel, so rubies with pigeon blood tones are more valuable. In addition, because the ruby ​​is filled with strong anger and rich colors, former people think it is the embodiment of a dead bird, and it has an ardent illusion. The origin of natural rubies is sparsely populated, the quality of ruby ​​is only produced in Myanmar, and the output is gradually decreasing. Now it can be said that almost the decline is exhausted, and the big stone no longer appears.

Evaluation and purchase of rubies. The primary evaluation and purchase factor for rubies is color, followed by weight, transparency and clarity. In general, the color is pure, the particles are large, transparent, with little or no inclusions and flaws, and the processing is fine. The proportioned faceted rubies of all parts are the best. Burmese rubies, mostly pigeon blood red, uniform color, high transparency, large grain, very few flaws and cracks. Sri Lanka ruby, light color, the main variety is star ruby. Thai sharp bamboo ruby, deep red, not too bright, relatively clean. Ruby is brittle, afraid of knocking, beating, and should be taken care of when wearing.