Sapphire is produced in Thailand, Sri Lanka, Madagascar, Laos, Cambodia, China, Changle, Hainan, and Sun Shi Mountain in Jiangjin, Chongqing. Among them, the rarest origin belongs to the sapphire in Kashmir, and Myanmar is the place where the highest quality sapphire is produced today.
Sapphire is characterized by uneven color, and parallel hexagonal columns are arranged with flat bands and growth lines of different shades. 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.
Identification method
Sapphire is as precious as ruby. If the color, clarity and cutting are good, the price will be high. Small ones often cost tens of thousands of yuan. However, there are many fake sapphires on the market, so we must be careful. It doesn't cost much to buy a high-quality sapphire, and most of them are deceived.
Sapphire belongs to the category of jewelry. At present, collecting jewelry is very common. But in the process of buying and selling collections, the most important thing is to learn some appraisal knowledge.
The most common sapphire on the market is glass. In fact, it is relatively easy to identify glass. Glass is shaped at high temperature, naturally shrinks after cooling, and the plane is concave inward. This kind of depression is not easy to find with the naked eye, so a magnifying glass must be used. When using a magnifying glass, you can't focus in a straight line, but focus obliquely, so it is easy to find the concave surface. The concave surface is usually glass. The polishing of precious stones usually achieves a very flat effect. Another identification method is that there are many kinds of inclusions in glass, the most common one is bubbles, while gems have no bubbles. Bubbles in glass can be found with a magnifying glass of 10 times.
There is also a sapphire that acts as a synthetic sapphire. The identification method is to first look at the texture and whether the texture structure is naturally crystallized. Rock crystal is often messy, so it is generally genuine. However, the crystallization of synthetic sapphire is often very orderly. Of course, many synthetic sapphires are clean and flawless, usually fakes. Because there are always some impurities in natural gems, there are almost no clean ones. This synthetic sapphire is often dazzling in color and superficial in luster, without the deep feeling of natural color. Natural gemstones are high in color purity, not dazzling, and their brilliance is naturally emitted from the inside out.
Glass: cobalt
Synthetic spinel: same as above.
Sandwich stone: the upper part is real sapphire and the lower part is fake. Put the stone into the water and carefully observe the different colors, luster and contents of the waist.
Spinel: Single refraction, different refractive index.
Tanzanite: Different physical properties.
The world's largest cut sapphire-"Oriental Blue Giant", a rectangular sapphire from Kashmir, weighing 486.52 carats, is a rare treasure in global jewelry.
Distinguish blue tourmaline from aquamarine.
There are many ways to identify two kinds of gems. The most direct way is to observe the gem you want to buy and judge it from its color and inclusion. Generally, the color of blue tourmaline is dark, and aquamarine is light blue. Aquamarine is generally light blue, which is the color of shallow water or light sky blue, and some aquamarine is green and light blue-green.
Secondly, the inclusions in gems can also help you distinguish between two kinds of gems. The inclusions in tourmaline are mostly liquid or flat thin-layer interstitial inclusions, while those in aquamarine are mostly rain-like inclusions. Generally, it is difficult for the naked eye to see the content of sapphire with good quality, and it can only be seen with the help of a magnifying glass.
Of course, we can also distinguish blue tourmaline from aquamarine from other aspects. Tourmaline is polychromatic, aquamarine is polychromatic. There is no obvious difference in hardness between the two. The density of tourmaline is higher than aquamarine, so the blue tourmaline with the same volume is higher than aquamarine.
Identify blue natural gemstones similar to sapphires.
Blue natural gemstones similar to sapphire include blue spinel clock, blue tourmaline, tanzanite (zoisite), blue zircon (discoloration), blue cone mineral, kyanite and cordierite. Artificial gem is similar to synthetic sapphire, synthetic spinel and glass. Sapphire has unique distinguishing features: uneven color and parallel flat strips; Including spun silk inclusions, dispersed liquid inclusions and lotus leaf inclusions, with strong dichroism. Similar natural blue gems differ as follows:
Spinel: Blue spinel is uniform in color and slightly gray in tone. Isotropic, there is no dichroism. There are many gas-liquid inclusions and octahedral small spinel inclusions in the crystal.
Blue tourmaline: mostly bluish-blue, multi-fractured, hollow tubular gas-liquid inclusions. The birefringence is very large, and double shadows can be seen at the edge of the bottom facet. Dichroism is extremely obvious.
Blue Cone Mine: The only place in the world is California. The output is not large and the particle size is small. Blue cone ore is blue to purple. The refractive index and density are similar to those of sapphire, and it also has strong dichroism. But it has large birefringence (0.04) and strong dispersion (0.044). Therefore, it has a bright appearance of strong dispersion, birefringence and bright blue fluorescence under short-wave ultraviolet light, which can be distinguished from sapphire.
Blue zircon: Zircon treated by electric potential is bright blue, which is distinguished from sapphire by its strong dispersion (0.039), high birefringence (0.04-0.06) and closely arranged absorption spectrum.
Tanzanite (zoisite): It is a gem-grade zoisite found in Tanzania, referred to as Tanzanite for short. It is one of the most popular gemstone varieties in the world at present. Zoisite is reddish brown, deep purple, transparent and large, and turns into sapphire indigo after heating. The colors are uneven, and there are three obvious colors: dark blue, purple red and yellow green. The density is 3.35g/ cm2, and the hardness is 6.5-7, which are lower than sapphire and can be distinguished from it. The blue color of zoisite is caused by 0.02-2% vanadium, so there is no absorption line of iron in the absorption spectrum.