“crazy” stone
There is probably no one who does not know the famous slogan “Diamonds are forever, one piece will last forever”. Under the operation of the jeweler, a member of the gemstone family—diamond is defined as a symbol of love, the price soars, and it starts its own “open” life.
Gemstones are a beautiful and valuable class of minerals. They are bright in color, crystal in texture, brilliant in luster, hard and durable, and rare in occurrence. They are natural mineral crystals that can be used for decoration and other purposes. It is said that gemstones are the uncanny workmanship of nature, and their formation requires extraordinary geological conditions. The gemstones we see in shopping malls are cut, shaped and polished from rough gemstones.
Since ancient times, gemstones have been sought after and loved by people, especially women, who are more willing to wear gemstones on their bodies to set off the charm of their appearance and show their dignity. Emerald, spinel, corundum red sapphire, each of which is a gemstone that has been loved by royal families and nobles throughout the ages. They are so beautiful and valuable that ordinary people can’t match them.
The earliest time when people used gemstones can be traced back to around 4000 BC. Archaeologists discovered in the Middle East that the seals used by people at that time had begun to be made of hard gemstone materials. In more than 3000 BC, the gem trade began to develop. Gems at that time not only had decorative value, but were often endowed with some supernatural powers. Due to their rarity and beauty, gemstones are used as amulets to provide protection, good luck, love and wealth.
However, for scientists, the value of gemstones is another matter. In the 17th and 18th centuries, the research on the physical properties of gemstones directly promoted the development of chemistry, optics and crystallography. Now that people are finally able to understand why those magical gemstones produce such dazzling colors, new gemstones and new treatments of traditional gemstones are constantly being discovered and invented, which also adds to the diversity of gem beauty and function.
The beauty of gemstones lies not only in the beauty of color and craftsmanship, but also in the beauty of materials. They have high hardness, special chemical composition, and unusual internal structure, which cause light reflection, refraction, scattering, interference, diffraction and other phenomena. Under the background of gemstone color, transparency and shape, optical physics The phenomenon unfolds like a dream. However, gemstones can not only be used as radiant jewelry, but also have very important application value in the industrial field.
Cutting and Grinding Materials
Beauty, durability and rarity are the three basic elements of gemstones, among which durability means that gemstones usually have high hardness, and the most representative one is diamond, that is, diamond.
Purely from the perspective of mineral composition, there is nothing special about diamond. It is composed of carbon elements, but each carbon atom inside the diamond is connected with other 4 carbon atoms to form a regular tetrahedral space three-dimensional network structure. It is a strong whole, which determines that diamond has extremely high hardness and chemical stability, making it the hardest mineral in nature, and also determines its important value in industry.
Cutting and Grinding Materials – Garnet
Diamond is an ideal tool for cutting, grinding and polishing, and can be used to make knives, drills and abrasives. For example, geologists need hard drill bits when drilling into the ground. The drill bits are embedded with some tiny diamond particles, which can wear down and drill through underground rock. In addition, saws made of diamond can be used to cut stone, diamond knives can be used to cut glass, and diamond fine powder with a diameter of less than 1 mm is very suitable as an industrial abrasive to make grinding wheels or belts.
The abrasive materials commonly used in industry include garnet, especially the relatively hard almandine and andandroid, which are the most widely used. First of all, it has high hardness (Mohs hardness is 6.5-7.5), high melting point (1180-1200°C), uniform particle size, and can be used for grinding optical instruments, electronic components, glass, ceramic products, etc. Secondly, because of its strong weathering resistance, it can be used to build airport runways and anti-skid road surfaces on highways; in the field of petroleum industry, it can also be used to clean drill pipes and casings for oil drilling.
optical material
Sapphire and ruby are sisters, they both belong to corundum, the main component is aluminum oxide. The color of ruby is due to the trace amount of chromium contained in corundum. If the corundum contains trace amounts of titanium and iron, the appearance will be dark blue, which is sapphire. Because red sapphire has good optical properties, mechanical properties and chemical stability, it has a wide range of applications in industrial fields such as semiconductors, optoelectronics and communications.
In order to meet the needs of industry, artificial rubies and sapphires can be produced in large quantities in the laboratory. As early as 1958, my country had begun to produce artificial rubies, which were used to make bearings for clocks and watches, or to make laser generators, etc. In 2011, Jiangsu, my country successfully developed the largest and heaviest artificial sapphire crystal in China at that time, with a mass of 101.35 kg. In February 2018, another giant artificial sapphire crystal was born in Inner Mongolia. It is transparent throughout, regular in shape, and has a total mass of 445 kilograms, setting a new world record. Such artificial sapphire is mainly used to make light-emitting diodes. Light-emitting diode is a semiconductor device that can convert electrical energy into visible light. It can increase the luminous efficiency by nearly 10 times, and its lifespan is more than 20 times that of traditional lamps. It has the advantages of green and environmental protection. It is often used in lighting and car lights. And notebook computers, LCD TVs, mobile phone display backlight and many other fields.
Optical material – ruby, produced in Yuanjiang, Yunnan
Spinel, which is similar in appearance to ruby, has “fake” the noble status of ruby more than once in history. In fact, it is a mineral composed of magnesium aluminum oxide. Later, with its bright red appearance and low price, it attracted a large number of gemstones. Lovers, become the “rookie” of middle and low-end gemstones in the jewelry industry. In industry, spinel also has important uses. Because it has good mechanical strength, high melting point, high temperature resistance, acid and alkali corrosion resistance, and wear resistance, it can be used to manufacture special optical instruments. The main material used in a transparent ceramic developed in the United States is magnesium-aluminum spinel, which has a melting point of over 2000°C and can withstand strong impact. Compared with metal materials, it not only greatly reduces the quality, but also can pass through specific bands of light. It has important uses in the military field, such as the raw materials for tank windows and soldiers’ protective masks.
refractory material
There is also a “rookie” in the gem family called kyanite, a silicate mineral that is mainly formed in metamorphic rocks. Normally, kyanite crystals are mostly light blue elongated columns with a bright glass luster on the surface, and the closer to the center of the crystal, the more intense the color. Some people describe it as a “blue popsicle”, which is really vivid.
Kyanite, which can be used as jewelry, has an important use that is not well known to everyone-it is used to make advanced refractory materials. Scientists have discovered that kyanite has a very remarkable characteristic, that is, when it is heated above 1100°C, it will expand significantly, with an expansion rate as high as 11% to 18%, but it hardly shrinks after cooling. However, most clay refractory materials will decompose or dehydrate at high temperature, thus shrinking, deforming or even cracking. If a certain amount of kyanite is added to such a refractory material, it can offset the volume change, thereby ensuring the volume stability of the refractory material. It can be used to manufacture refractory bricks, refractory cement and industrial kilns, etc., and its service life can be greatly extended.
In addition, kyanite is also very suitable for the manufacture of refractory ceramics, such as spark plugs on automobile engines, or for the production of silicon-aluminum alloys. It not only has light weight, high strength and good thermal conductivity, but also has good castability, wear resistance and corrosion resistance, and is often used in automobile manufacturing, shipbuilding and aerospace and other fields.
metallurgical material
Most of the metal materials used in our daily life come from the extraction of metal minerals, such as chalcopyrite, hematite, galena, etc., but a small part comes from precious stones, such as metal beryllium.
At the end of the 18th century, when the French mineralogist Ayuyi studied the two minerals, emerald and beryl, he found that their crystal geometric structures were exactly the same. Therefore, he suspected that the two substances should be the same mineral, but in order to ensure the accuracy of the inferred results, he asked the chemist Volkron to help identify them. The identification results show that the chemical composition of emerald and beryl is indeed exactly the same, and emerald is actually a kind of beryl. The more shocking discovery is that during the identification process, Volkron accidentally discovered that besides silicon and aluminum oxide, there is a new substance in beryl. In February 1798, Volkron announced his discovery and named the substance “beryllium”. However, due to the limitation of technology at that time, it was very difficult to extract beryllium. It was not until 1828 that scientists isolated the metal beryllium from the compound.
Beryllium is the lightest alkaline-earth metal element, one-third less dense than aluminum, much stronger than steel, and has remarkable corrosion resistance. Adding a small amount of beryllium to copper can make an alloy that is both corrosion-resistant and extremely tough. If it is used to manufacture aircraft parts, it will greatly reduce the quality of the aircraft and improve the maneuverability of the aircraft. There is a supersonic fighter that uses metal beryllium, which can fly at a speed of 4000 km/h, which is more than three times the speed of sound.
In addition to beryl, spodumene, amazonite, zircon, etc. can be used to refine metals. Spodumene is a kind of pyroxene rich in lithium element. Spodumene crystals in nature are usually columnar or plate-shaped, with glass luster. Lithium metal, the raw material required for the manufacture of lithium batteries, is mainly extracted from spodumene of. Tianhe stone belongs to a kind of feldspar, and its color is usually green or blue-green. Since this gemstone contains rubidium oxide, it is commonly used in industry to extract rubidium metal. Zircon is a zirconium-containing silicate, which can be used not only to extract metal zirconium, but also to extract metal element hafnium.
piezoelectric material
In 1880, the French chemists Pierre Curie and Jacques Curie found a strange characteristic of crystal: when the crystal is subjected to compressive stress or tensile stress in a certain direction, it will cause the crystal to be perpendicular to the stress. Opposite charges are generated on the two surfaces. If the mechanical pressure acts alternately one by one, an alternating electric field can be generated, which is the famous “piezoelectric effect”.
So, what is the use of this physical property? Don’t underestimate it, the piezoelectric effect of the crystal has played an important role in the war. During World War I in 1914, German submarines dealt a major blow to the Allies. Discovering and accurately locating the elusive German submarine became a major problem at the time. Physicists tried every means to invent an echo detector based on the characteristics that sound waves can travel far in water and have little attenuation. The most important part of the echo detector is the transducer, which can convert sound energy, mechanical energy, and electrical energy into each other, and requires high sensitivity. The selection of materials is very important. The famous French physicist Paul Langevin thought of the piezoelectric effect discovered by the Curie brothers, so he found a quartz crystal to make a transducer, and successfully searched for the echo of the submarine submarine through experiments. However, it is a little regrettable that this invention came out a bit late, and the First World War was over before it had time to show its talents in the war. Nevertheless, the discovery of the crystal piezoelectric effect and the invention of the echo detector played an important role in promoting the development of sonar technology. Today, crystals are widely used to manufacture high-precision piezoelectric quartz components, such as resonators, filters, etc., which are important components in modern defense and electronics industries.
Piezoelectric materials – crystals with inclusions
There is also tourmaline, which has a piezoelectric effect, namely tourmaline. Not only that, but when tourmaline is heated, it can also have a positive charge on one end and a negative charge on the other end, a phenomenon known as the “pyroelectric effect.” The word “electricity” in the so-called “tourmaline” comes from this. Using these special properties of tourmaline, people can make many high-precision electronic components in the modern defense industry and electronics industry.
