The above has introduced jadeite and various representative gems to you. In this section, I will tell you about agate. When we were young, we often listened to the old people. When we describe which family is rich, we say that their family is full of pearl agate, so when I was a child, I felt very mysterious when I mentioned agate. What exactly is this agate and how did it come into being?
Agate, also known as agate, Kate Ma and agate, is a kind of chalcedony mineral, which is often banded and lumpy with opal and aphanitic. The mineral composition is timely, the chemical composition is silicon dioxide, the hardness is 6.5-7 degrees, the specific gravity is 2.65, and the color is quite layered. Translucent or opaque. The primitive form of tripartite crystal system. It is often dense and massive, forming various structures, such as breast, grape and tuberculosis. The common structure is concentric circles. Chalcedony has different colors, usually green, red, yellow, brown, white and so on. According to patterns and impurities, it can be divided into onyx, silk-wrapped agate, moss agate, castle agate and so on. Often used as a plaything, ornamental, ornament or decoration. Agate balls can often be seen in ancient funerary objects.
Agate is a colloidal condensate of silicon dioxide, which is often in a circular concentric filiform or parallel strip structure. Its hardness even exceeds that of crystal. It is a hard, dense, exquisite and colorful gem, and it is also the first-class raw material for carving handicrafts.
How is agate made? Hundreds of millions of years ago, due to tectonic movement, underground magma invaded or ejected along the crustal fracture zone. When lava cools, steam and other gases form bubbles. When the rock condenses, the bubbles are sealed and many crystal holes are formed. After a long time, under the action of external dynamic geology, the crystal cave is gradually invaded by colloid containing silicon dioxide, which condenses into silica gel in the crystal cave and finally crystallizes into chalcedony. If the silica colloid fills the crystal hole, the agate body will be a concentric sphere; If the filling is not enough, agate crystal holes will be formed. Various cations, such as a small amount of iron ions, condense with it. After silica crystallizes into agate, various cations are mixed with it, which can present colorful brilliance.
The world-famous agate producing areas are: China, India, Brazil, Madagascar, USA, Egypt, Australia, Mexico and other countries. Mexico, the United States and Namibia also produce agate with lace stripes, which is called "lace agate". Yellowstone National Park, Wyoming and Montana in the United States also produce "landscape agate". Agate producing areas in China are also widely distributed, almost in all provinces. Famous producing areas are: Yunnan, Xunke, Heilongjiang, Liaoning, Hebei, Xinjiang, Ningxia, Inner Mongolia and so on.
The well-known agate in China is called Red, which refers to the agate mined in Beipiao, Chaoyang, Liaoning and Xuanhua, Zhangjiakou, Hebei in recent years. Before June 15, it was defined as a red onyx in gemology. It is the same material as some agate ornaments unearthed in the Warring States period, and this material was called ruby in the pre-Qin period, so this agate is called Warring States Red. During the Warring States period, the red agate in the Warring States period was mostly used as noble ornaments, such as ornaments, beads and rings. Thanks to the stable chemical properties of agate, the red agate unearthed in the Warring States period still maintains bright colors, and there is not much soil, which is no different from the red agate ore in the Warring States period today.
Many agate lovers don't know the origin of the name Warring States Red, and even say, "My agate ornaments are very old, which were formed as early as the Warring States Period." I guess he doesn't understand how long the warring States period is. The Warring States period is 2800 years away from today at most, and the formation of agate should be based on hundreds of millions of years. Therefore, it is necessary to explain the origin of agate red here!
? (4): amber
Speaking of amber, I think everyone will be familiar with it. I remember when we were in primary school, we all seemed to have learned an article about a fly that was wrapped in sticky rosin, then fell into the river, was buried by river sand for hundreds of millions of years, and finally formed amber. When people accidentally found it, it had been petrified into amber, and the flies inside were still lifelike. This is a popular science article when I was young.
Amber is a kind of transparent biological fossil, which is the resin fossil of Pinaceae, Pistaceae, Taxodiaceae and other plants. Resin dripped down and was buried underground for thousands of years. Under the action of high temperature and high pressure, petrochemical forms amber, some of which contain small insects such as bees, which is unusual. Amber is mostly formed by resin fossils of Pinaceae plants, so it is also called "turpentine fossil".
Amber has a variety of shapes, and the surface and interior often retain the lines produced when the resin flows, and bubbles and ancient insect, animal or plant remains can often be seen inside.
Common amber types: Jin Po, Jinlanpo, Green Tea Slope, Black Tea Slope, Blood Slope, Plum Slope, Brown Red Slope, Blue Slope, Green Slope, Insect Slope, Beewax, Pergen, Myanmar Root Slope, etc.
Amber is an organic mixture formed by geological processes of coniferous resin from Mesozoic Cretaceous to Cenozoic Tertiary. The formation of amber generally has three stages. In the first stage, resin is secreted from cypress. In the second stage, the resin was deeply buried and petrified, and the composition, structure and characteristics of the resin changed obviously. The third stage is that the petrochemical resin is washed, transported, deposited and diagenetic, thus forming amber.
On March 6, 20 16, Chinese scientists discovered the oldest amber ore in the world, with an age of about 99 million years.
Amber has low hardness, light texture, astringency, jewel-like luster and crystal clear. Another feature of amber is that it contains particularly rich inclusions, such as insects, plants and minerals. At present, amber popular in the gem market is beeswax.
? (5): pearls
Pearl is an ancient organic gem, which is mainly produced in mollusks such as Pinctada and Pinctada. The calcium carbonate-containing mineral (aragonite) beads produced by endocrine function consist of a large number of tiny aragonite crystals; Rich in variety, different in shape and colorful; According to the research of geology and archaeology, there were pearls on the earth 200 million years ago. In the international gem circle, pearls are also listed as lucky stones for June birthdays and commemorative stones for 13 and 30th wedding anniversaries. Pearls with magnificent colors and elegant temperament symbolize health, purity, wealth and happiness, and have been loved by people since ancient times. Pearls are divided into freshwater pearls and seawater pearls.
How are pearls formed? There are two ways to form. First of all, mussels or brachiopods, bivalves in the sea, sand and other foreign bodies are accidentally involved in shells, just like people's eyes entering foreign bodies. People can wash away foreign bodies by hand, but animals can't, but they also have their own unique methods, which can continuously secrete mother-of-pearl to wrap foreign bodies bit by bit. In this way, the nacre layer will accumulate smoothly, the shellfish will be dissolved and pearls will be formed. The inner core of this kind of pearl is very small, which is a foreign body initially involved in the shell. Another way of pearl formation is that the shells of bivalves are accidentally damaged and organisms leak out of the shells. In order to avoid the damage of organisms, it has to constantly secrete nacre to repair the damaged shells, so that pearls have formed for a long time where the shells were originally damaged. This kind of pearl is characterized by irregular shape and no inner core.
Chemical composition of pearls: The inorganic components of pearls are mainly calcium carbonate and magnesium carbonate, accounting for more than 9 1%, followed by silicon dioxide, calcium phosphate, Al2O3 and Fe2O3.
The organic matter in pearls contains 17 amino acids such as aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cystine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, arginine and proline. In addition, it also contains more than 30 kinds of trace elements, taurine, rich vitamins and peptides. Therefore, pearls can be used not only as handicrafts to beautify people's lives, but also as medicines to save people's lives. It is no exaggeration to say that they are gems!
Pearl has various shapes, such as round, pear-shaped, egg-shaped, teardrop-shaped, button-shaped, arbitrary shape, etc., among which round is the best. Not an isotropic body. Colors are white, pink, light yellow, light green, light blue, brown, lavender, black and so on. , mainly white. White stripes. It has typical pearl luster, soft luster and rainbow color. Transparent to translucent. Refractive index 1.530- 1.686, birefringence: aggregate is unmeasurable. There is no dispersion. The hardness is 2.5-4.5. The density of natural freshwater pearls is generally 2.66-2.78g/cm3, which varies from place to place. No cleavage. Good toughness. White pearls are light blue to light yellow under short-wave ultraviolet irradiation; Yellow and golden pearls are yellow-green, green-brown to dark brown; Black pearls are usually pink to orange-red; There is yellow-white fluorescence under X-ray. Foam in hydrochloric acid.
Nowadays, fishermen by the sea breed pearls in large quantities according to the mechanism of pearl formation, and their income is quite rich! Products can be sold not only to handicraft shops, but also to pharmaceutical factories. Artificial pearls are almost the same as natural pearls, but the colors are not as bright as natural pearls.
? (vi): Conclusion
There are too many kinds of jewels and jade in the world. Because of the author's cognitive level and theoretical level, I will only introduce some jewels and jade articles that you usually hear or see. Although there are many kinds of gems, the mineral composition and chemical composition are similar, basically just a few. Several minerals are combined together, just like the 26 letters in English, to form different words. The same is true for them. Several minerals combine separately to form different substances. As mentioned at the beginning of this paper, they are nothing more than high purity and highly uniform composition, forming substances different from other ores and surrounding rocks-so gems were born!
There are seven main rock-forming minerals on the earth. Of course, there are many metamorphic minerals formed on the basis of these seven minerals. These seven main rock-forming minerals are quartz, feldspar, mica, amphibole, pyroxene, olivine and aragonite. The chemical components of these minerals are silica, alumina and calcium carbonate. Fe2O3, magnesium carbonate, Na2O,? K2O, FeO, P2O5 and so on, so I won't list them one by one.
With the improvement of science and technology, a large number of artificial gem have been produced. For example, using graphite to produce diamonds, using bauxite to produce rubies and sapphires and so on.
Perhaps the reader wants to say: since there are only a few chemical components, there are not many minerals, and some substances have exactly the same chemical elements, why are things formed in nature so different? Here are two technical terms. Let me briefly say that one is called allotrope and the other is called isomer, which is also called isomorphism or isomorphism. Allomorph refers to the chemical elements that make up a substance, that is, simple substance. Because the atomic framework of this element is different, different surface substances are formed. Compared with diamond (c) and graphite (c), it is composed of carbon, which is because the atomic structure is different, resulting in the highest hardness; One is low in hardness, and the other is non-conductive and non-thermal; One is extremely low resistivity, that is, thermal conductivity and electrical conductivity, and the other is transparent regular polyhedron; One is a black layered substance. Similarly, there are red phosphorus (P) and white phosphorus (P).
Isomorphism means that the molecular units or chemical formulas of constituent substances are the same. Molecules with different structures or functional groups that can form substances form different crystals, and of course the phase states are also different. For example, ruby, sapphire and bauxite have the same chemical molecular formula (Al2O3) and are all alumina. However, due to the different arrangement structure of molecules, the properties of constituent substances are also very different. Similarly, there are crystals (silica) and diatomaceous earth (silica).
This is the mystery of chemistry, and this is the magic of nature. Just like our food, pork and bear's paw are composed of hydrocarbons, oxygen and nitrogen, which can satisfy hunger when eaten in the stomach, but the quality and taste are completely different! With the improvement of people's living standards, people have higher expectations for the quality and taste of life. They should not only "satisfy their hunger" but also "taste" the beauty of life!