Folding variety identification

Amethyst: a kind of purple crystal, which is caused by the trace iron contained in SiO2. Upon irradiation, one of the paired electrons in the electron shell of the trivalent iron ion is excited to produce a hole color, and the hole is mainly in the visible light at 550nm The crystal produces purple due to production and absorption, but ferroferric oxide is unstable and easily turns into ferric iron when heated, so amethyst is easy to fade, and the color distribution of amethyst is often uneven and clumpy. Sometimes parallel color bands are seen. . With weak to moderate dichroism, all inclusions that appear in crystals may appear, as well as characteristic "zebra patterns" and spherical, droplet-shaped opaque dark inclusions.

 

Topaz: A yellow crystal containing trace iron in its composition. Topaz is generally transparent and has the same internal characteristics as amethyst. Most topaz on the market is made of amethyst by heating.

 

Green crystal: a kind of green crystal, which is rarely produced naturally, mainly obtained by heating amethyst; or the crystal contains green minerals (such as chlorite) inclusions and is colored.

 

Hibiscus stone: also known as rose quartz, light to medium pink crystal, lighter tone, colored due to traces of Mn and Ti in the composition, less single crystals, usually dense massive aggregates, showing a cloudy and milky appearance, sometimes It can contain needle-shaped rutile inclusions arranged in a directional arrangement, so that it can be ground into a curved gemstone to show stars.

 

Two-color crystal: a kind of crystal in which purple and yellow coexist together. Purple and yellow respectively occupy part of the crystal block. There is a clear boundary between the two colors. The two-color is caused by the double crystal in the crystal. Purple and yellow develop separately. The r-plane and z-plane in the twin crystal monomer. Quartz cat's eye: When the crystal contains a large number of parallel-arranged fibrous inclusions, the curved surface of the gemstone can show the cat's eye effect. Generally, the curved surface of the quartz cat's eye is higher and the fibrous inclusions are clearly visible.

 

Starlight crystal: When the crystal contains more than two groups of needle-like and fibrous inclusions arranged in a directional arrangement, the surface of the cambered gemstone can show the starlight effect, which is generally six-ray starlight or four-ray starlight.

 

Aventurine: It is a kind of quartzite with aventurine effect. The green aventurine containing chromium mica is commonly seen in the market. It is slightly transparent under the microscope and is mainly produced in India. Quartz particles are relatively thick, 0.1-0.6mm, and the flaky minerals contained therein are relatively large, and they are arranged roughly in orientation. It is slightly maroon under the Charles filter.

 

Miyu: It is named after being produced in Mi County, Henan Province. It is a dense quartzite containing 3 to 5% of fine scaly sericite. It is mainly green series, such as light green, emerald green, and bean green. Compared with Aventurine, Miyu is more delicate and dense. The quartz grains in it are mainly 0.02~0.25mm, and there is no obvious aventurine effect. When magnified and inspected, at higher magnifications, you can see that the fine green mica is more evenly distributed in a network. Guicui: It is named because it was produced in Guizhou Province. It is a fine-grained quartzite containing green kaolinite. It has an uneven green with gray tones. It is generally only used for low-end jewelry.

 

Jingbaiyu: Named because it was originally produced in the suburbs of Beijing, it is a white quartzite with fine texture and luster. It is sometimes used to pretend to be mutton white jade. It is distinguished by its lower density and refractive index.

 

Chalcedony: an aggregate of ultra-microscopic cryptocrystalline quartz, the single crystal is fibrous, the intergranular micropores are filled with water and bubbles, and the density is lower than that of quartz, about 2.60g/cm. Because chalcedony is porous, it is easy to dye. The brightly colored chalcedony that is common on the market is dyed. It is worth mentioning that the color of the dyed chalcedony is relatively stable, and it is also a low-grade jade.

 

Agate: Chalcedony with a ring-shaped structure. The center of the ring is sometimes hollow and sometimes filled with crystal. The most common natural colors of agate are white and gray, but also yellow-brown, brown-red, blue, and lavender. Wait. The basic properties of agate are the same as chalcedony. According to the characteristics of the inclusions, the color distribution has the following special varieties.

 

Moss agate: a uniform, translucent chalcedony containing dendritic green chlorite or black manganese oxide and red iron oxide. The wrapped impurities are often moss-like, and are generally used as ornamental stones, also called scenic agate, which is a valuable species in agate.

 

Onyx: Also known as striped agate, it is a kind of agate with relatively simple color and relatively straight strips. It is usually used for stone carvings and relief sculptures. Common agates can have black and white strips, or red and white strips. When the strips of onyx are as thin as silk, they are called sardonyx.

 

Water gall agate: It is a variety that contains gas-liquid inclusions that are visible to the naked eye, and the gas-liquid inclusions can move when rotated.

 

Jasper: It is a kind of chalcedony with a lot of impurities. The main impurity is iron oxide, so jasper is often red, but it also has other impurities that make it green, dark blue or black. Jasper is opaque and has a dim luster. It is a kind of bands of different colors, and the color blocks complement each other. The jasper that looks like a beautiful natural landscape is called landscape jasper; a dark green jasper with red dots on it is called blood drop stone.

 

Australian jade: It is a kind of green chalcedony, which is green due to the trace nickel. It is more uniform in color and transparent to translucent. It is mainly produced in Australia.