The name of tourmaline is tourmaline, and the English name is tourmaline, which comes from the ancient Sinhala language? Turmali? From the word, meaning? Mixed gems? . In some historical documents of our country, it is called? Selenium? 、? Tourmaline? 、? Bi Xia Xi? 、? Broken evil gold? Wait a minute.
Tourmaline crystal Tourmaline is a complex triangular columnar crystal, and there will be characteristic growth stripes on the surface of the crystal parallel to the extension direction of the columnar crystal. In cross section, it is a curved spherical triangle.
The color of tourmaline The color of tourmaline is the most abundant among all kinds of precious stones. Tourmaline belongs to a complex borosilicate mineral, and its chemical molecular formula is Na (Mg, Fe, Mn, Li, Al) 3L6 [Si6O 18] 3 (OH, F) 4, in which metal ions such as iron, magnesium, lithium, manganese and aluminum can be substituted for each other, and the different content of each ion will directly affect the different colors and types of tourmaline. Iron-rich tourmaline is dark green; Magnesium-rich tourmaline is yellow or brown; Tourmaline rich in lithium, manganese and cesium is rosy, pink, red or blue; Chromium-rich tourmaline is dark green. Among them, blue and bright rose tourmaline are top grades. In the same tourmaline crystal, the uneven distribution of components often leads to color changes, such as two-color tourmaline, multi-color tourmaline or watermelon tourmaline with infrared green inside.
Polychromaticity of tourmaline
In addition to its colorful colors, tourmaline is most attractive because of its polychromatic color. When we hold tourmaline and observe it from different angles against the rotation of light, the color, tone and depth of tourmaline will change with the change of observation angle. This is due to the strong multicolor of tourmaline, which also gives tourmaline a mysterious color.
Piezoelectric effect and thermoelectric effect of tourmaline
When tourmaline is heated or pressed, or rubbed by silk or wool, it will produce electrode effect at both ends of columnar tourmaline, one end is positive and the other end is negative, which will make tourmaline absorb some dust or small pieces of paper. The magical power is the piezoelectric effect and thermoelectric effect of tourmaline, right? Tourmaline? The origin of this name. There is an interesting story: it is said that in 1703, on a warm summer day in Amsterdam, the Netherlands, several children were playing with stones brought back by Dutch navigators. Suddenly, a child found that dust and grass clippings near these stones were sucked in. The children were surprised and called their parents to see it. Sure enough, they found that this stone can attract or repel light objects, such as dust and grass clippings. From then on, the Dutch called it a "dust stone" and used it to clean the soot in the pipeline.
Cat's eye effect of tourmaline
Tourmaline crystals are rich in gas-liquid inclusions, which are often distributed directionally to form tubular inclusions. Will dense tubular inclusions make tourmaline into arc or round beads with cat's eye effect? There are obvious bright bands on the surface of tourmaline, and the bright bands change with different observation angles.
Second, the identification of tourmaline tourmaline has rich colors and magical effects, making tourmaline jewelry one of the first choices for today's popular jewelry. But how to identify and select tourmaline? Gems similar to red tourmaline include ruby, red spinel, spodumene, red topaz, red beryl, lavender crystal and so on. Gems similar to green tourmaline are diopside, emerald and green beryl. Gems similar to blue tourmaline have blue spinel. In addition, glass imitation is also one of the varieties easily confused with tourmaline. In the identification of tourmaline, the key points are as follows:
1) tourmaline has a high density (3.06) and is heavier than crystal and glass when measured by hand;
2) Rich colors. Tourmaline is one of the most colorful gems. Different colors can appear on the same crystal, such as yellow and green, pink and yellow, red and blue.
3) Polychromaticity is obvious. Tourmaline will change in color, hue and brightness when viewed from different angles under transmitted light, while amethyst is not obvious and glass will not appear.
4) Obvious birefringence ghost effect. The refractive index of tourmaline is 1.6 16? 1.650, the birefringence can reach 0.044, and the facet edge and impurities on the back will have obvious ghost effect when observed through tourmaline crystal with a magnifying glass;
5) electrostatic effect. Tourmaline has thermoelectric effect, which can absorb fine dust and paper scraps after friction and heat generation;
6) tolerance. Directional linear and tubular vapor-liquid inclusions often appear in tourmaline internal inclusions; Crystal and topaz are mostly irregular point-like and feather-like inclusions; Bubbles and vortex lines will appear on the glass.
7) growth line. For natural tourmaline crystals, the main characteristics different from beryl are triangular cylinders with curved surfaces and growth lines parallel to the extension direction of the cylinders.
Third, the purchase of tourmaline The purchase of tourmaline mainly focuses on the following aspects:
1) color. Tourmaline is more precious in red and blue, and yellow and green are more common. In the choice of tourmaline jewelry, red, blue and green are the best, and the colors are required to be uniform and gorgeous; Among necklaces and bracelets, it is best to have rich colors. The color of each bead can be different, including red, yellow, blue, green and purple.
2) transparency. Tourmaline requires crystal clear, the more transparent, the better the quality, and there can be no obvious fog or opacity;
3) purity. Tourmaline is fragile and prone to cracks. It also contains a lot of inclusions. The existence of a large number of cracks and inclusions will affect the transparency, color and fire color of tourmaline, and the tourmaline with very pure interior is also rare and belongs to the top grade. When choosing, try to choose the one that is clean inside.
4) Pay attention to the selection of tourmaline with special performance. Tourmaline is rich in color, and two or more colors appear on the same tourmaline, that is, two-color tourmaline or multi-color tourmaline, and the watermelon tourmaline with infrared green inside is also more precious; In addition, tourmaline cat's eye belongs to the top grade of tourmaline.
Tourmaline is colorful and changeable, and it has peculiar piezoelectric effect and thermoelectric effect, which makes people believe that tourmaline has the magical power of nature. Long-term wearing can not only decorate people's lives, but also bring good luck, pray for peace and happiness, and bless their health. Therefore, nowadays tourmaline bracelets, necklaces, pendants, rings, brooches, earrings and so on. They all came into being at the historic moment, and they are constantly innovating, decorating the jewelry world that used to be dominated by platinum and platinum jewelry.