There is a story circulating in the West: 18世紀に, a hot summer in Amsterdam, the Netherlands, a few children were playing in the sun with some colorful stones brought back from overseas by voyagers, and found that these stones appeared in the sun. A strange phenomenon, they asked their parents to come and watch: their parents were surprised to see that this kind of stone has a power that can attract light objects such as dust or grass clippings, so the Dutch call this kind of stone “suction”. “Greystone” was later called tourmaline. In addition to being heated, tourmaline will also generate static electricity when subjected to friction or pressure, which is an important characteristic of tourmaline. This property is related to the heteropolar symmetry of the mineral crystals. According to this characteristic, the so-called tourmaline can be observed by friction: true tourmaline will absorb dust and become dirty easily.
Tourmaline is one of the minerals with the most complex chemical composition in nature. It is a complex borosilicate characterized by boron and aluminum. トルマリンは三方晶系に属します, and the crystals are compound trigonal long columnars. The aggregates are often rod-shaped, radial, and sometimes cryptocrystalline massive. Tourmaline has glass luster, 透明から半透明, and hardness is 7.0-7.5. トルマリンの化学組成は複雑です, because it contains different metal ions, there are many types, such as iron tourmaline, マグネシアトルマリン, and lithium tourmaline, and the colors are colorful. Those rich in iron are dark green, ダークブルー, ダークブラウン, and rich in magnesium. Those with brownish yellow, those rich in lithium and manganese are rose red and light blue; those with chromium are dark green. 加えて, there are two-color or multi-color tourmaline, which is caused by the distribution of two-color, three-color or even multi-color color bands or concentric layered color bands in the direction of the crystal long axis. 例えば, the middle part is purple-red, and the appearance The green ones are called “スイカトルマリン”.
近年では, tourmaline is very popular in the gem market, and the price is rising day by day.