"Polygonatum sibiricum" and topaz may be related to topaz, a fine topaz among topaz. In the past, topaz was also a relatively precious gem, and its precious value was only slightly lower than that of ruby and sapphire. The most precious variety was yellow-brown-yellow, which was similar in color to a rare snow plow wine in Spain and was called snow plow topaz commercially. Later, a large number of yellow crystals entered the market as Sydney topaz, which made the value of topaz plummet.
Topaz, as the birthstone of June 5438+0 1, is the best gift to express friendship. People wearing topaz can be used as amulets to eliminate sadness, ward off evil spirits and enhance courage and wisdom; In the west, some people even think that topaz has the efficacy of treating asthma, burns, bleeding and other diseases, and regards it as a symbol of wealth and piety.
1. Identification and evaluation of topaz
Identification of topaz
Topaz is a common gem, which is composed of fluorosilicate with hardness of 8, and its colors are colorless, pink, yellow and blue. The common gems that are easy to mix with topaz mainly include crystal, aquamarine, tourmaline and glass imitation, among which topaz is the easiest to mix together. In fact, except for the soft and fluffy appearance of topaz, it is extremely difficult for the naked eye to distinguish the two, which is also the fundamental reason why yellow crystals can cause people to doubt the value of topaz in the market.
It is easier to distinguish the raw materials of topaz and crystal. Topaz's columnar crystal surface has vertical stripes, while the crystal has horizontal stripes. Finally, the specific gravity (feel) of inlaid ornaments can also be used as a basis for distinction. The specific gravity of topaz is above 3.49, while that of topaz is only about 2.65. When you weigh it with your hand, topaz feels like a "falling" hand, while the crystal is lighter. Of course, the luster of topaz gem is soft, while the luster of crystal is "cold" and sharp, which can also be distinguished.
Topaz and tourmaline can be distinguished by the naked eye. The most important thing is that tourmaline is very dichromatic, while topaz is weak except pink. In addition, tourmaline has strong birefringence, and double images are often seen.
The difference between blue topaz and aquamarine is generally difficult, which can be used as a reference: blue aquamarine often has some yellow-green tones, a little dichroism and a light proportion. Accurate identification should be determined by refractometer.
The difference between processed glass and topaz is sometimes confusing. For example, in the United States, a yellow "gem" worth $65438+100000 fooled many experts. Even the data of refractive index and specific gravity (65,438+0.62 and 3.53) are similar to topaz. Later, someone noticed that its luster was too strong, so they used a polarizer to test it. As a result, the truth came out. It turned out to be a yellow glass.
Glass and topaz have different luster and polarization. Topaz is rock crystal, which has good heat transfer, so it feels very cold, while the glass is "warm". When magnified, topaz can sometimes see gas-liquid inclusions composed of immiscible liquids, and glass often contains spherical bubbles, which can be used as auxiliary evidence. After identification, the key topaz is soft in luster and heavy in proportion.
Evaluation of topaz
There are several factors to evaluate topaz, and color is one of the most important criteria. Generally speaking, purple, pink and Sydney yellow are more expensive, while blue and colorless are more common. The depth of color is also very influential, and the color of topaz is often more valuable. In addition, the size, cutting style and processing quality of gems all have an impact on the price. Under normal circumstances, topaz can't be flawed, and it should be removed during processing. If the processed topaz is defective, the bargaining price will be much lower.
The yellow, pink and orange-red topaz of main wines are of high value.
2. Origin of topaz
Topaz is produced all over the world. The most important gem-grade topaz is produced in minas gerais, Brazil, where topaz is yellow, deep Sydney yellow, pink, blue and colorless. Sri Lanka is also an important producing area, and its topaz is mainly blue, green and colorless. California produces blue and yellow topaz.
A large number of colorless topaz produced in Guangdong, Xinjiang, Yunnan and other places in China can be turned into beautiful sky blue by neutron radiation, electron accelerator bombardment, Co60 irradiation and heating. It is worth noting that topaz discolored by neutron radiation is radioactive and needs to be left for a certain period of time (such as more than half a year) before it can be used as a decorative gem, otherwise it will cause certain harm to human body.
Once upon a time, many people were frightened by the radioactivity of topaz. In fact, it took more than half a year from changing the color of raw materials or blanks to processing them into rings and then inlaying them into jewelry. Topaz changed with Co60 is not very radioactive, so it is not necessary to be too sensitive to the radioactivity of the changed topaz.
3. Tips for buying topaz jewelry
(1) First of all, pay attention to the color when buying topaz. Bright and pure wine yellow and orange topaz are good products.
(2) Gemstone processing should be standardized and bright, and there should be no cracks, defects and edge collapse.
(3) Ask whether the color is natural or radiant.
Topaz is topaz.
Huang Yushi not only has charming and beautiful colors in autumn, but also is a gem with many colors, such as bright orange yellow like Sydney, noble violets, fiery red, hearty blue, elegant light green and even colorless like water drops. ...
Historically, topaz used to be a kind of hard-to-find gem, just like that foggy island, it was almost hard to find. Moreover, topaz is one of the most easily confused gems with other gems, and it is often mistaken for other gems, such as the Portuguese royal jewels mentioned above, which are mistaken for diamonds. Topaz, a foreign name, seems to reveal the mystery of what it calls a gem.
For a long time, it was generally believed that topaz was yellow. Jewelry circles in Chinese mainland, Hong Kong and Taiwan have long been used to calling topaz "topaz" or "topaz". In fact, pure topaz is colorless; Colored topaz includes blue, light green and all colors in the spectrum, from yellow to common Sydney orange yellow and pink, and even extremely rare red.
Although Topaz was recorded in ancient Egyptian and Roman literature, it was not very famous until the Middle Ages, and it was only occasionally used by the royal family or the church. But in the18th century, topaz became famous. In France and Spain, topaz and diamonds are set in many gorgeous jewels. /kloc-At the beginning of the 9th century, necklaces, earrings and other jewelry made of topaz and amethyst were popular in France and Britain. Topaz was still one of the most popular gems in Victorian times. Famous jewelers from World War I to World War II also attached great importance to topaz. Topaz has always been regarded as the best yellow gem and is deeply loved by people.
On the Mohs hardness scale, the hardness standard of topaz is 8; Colorless topaz has excellent luster, and the lathe operator has a good colorless topaz that shines like a diamond. Among the Portuguese royal jewels, there is a gem weighing 1.680 carats. The brilliance of this gem is fascinating. For centuries, it has been named after the royal family and is called "Braganka Diamond". According to expert appraisal, this is actually a colorless topaz without impurities. Colorless topaz with such large particles and good quality is really rare, and it is worthy of being a royal collection.
1 1 century, Europeans believe that topaz can treat eye diseases. Soaking topaz in wine for three days and nights, and then massaging the sick eyes with it can not only treat common eye diseases, but also have a good effect on amblyopia. The Book of Wings in the 3rd century in Europe records that topaz engraved with falcon patterns can help the wearer, especially the powerful people, cultivate friendly feelings. It was recorded in later literature that topaz can treat epilepsy and increase a person's wisdom and caution, and it is the coolant of boiling water and anger. Topaz is favored for its color, transparency and hardness.
The physical properties of topaz are so unique that its surface is as beautiful, smooth and dazzling as velvet. Its mass varies from a few carats to hundreds of kilograms of large stones.
Color and clarity are two important factors in evaluating topaz. Red topaz is extremely rare and is the most expensive topaz; Topaz, the color of Sydney, is gorgeous and has always been loved by people. The prices of Sydney colors (brown, orange, reddish brown) and pink topaz are also higher. Topaz, commonly used in western jewelry industry, refers to yellow topaz, which is used to distinguish yellow topaz from other colors.
In recent years, mainland consumers are increasingly interested in topaz. Indeed, as the birthstone of June 5438+0 1, topaz has charming beauty, and no matter who wears it, it will be shocked by its beauty, wisdom and harmony.