Diamonds emit blue-green fluorescence under X-ray irradiation. Diamonds are found only in kimberlite cones. Kimberlite is the original stone of diamonds, and diamonds from other places are transported by rivers and glaciers. Diamonds are generally granular. If the diamond is heated to 1000℃, it will gradually become graphite. 1977 A villager in Changlin, Jishan Town, Linshu County, Shandong Province found the largest diamond in China (about the size of an egg yolk, right). The world's largest industrial diamonds and gem-grade diamonds are both produced in Brazil, both exceeding 3 100 carats (1 carat = 200mg), among which the gem-grade diamonds are 10×6.5×5cm, which is called "Cullinan". In 1950s, the United States successfully manufactured synthetic diamonds from graphite at high temperature and high pressure. Now synthetic diamond has been widely used in production and life, but it is still very difficult to manufacture large-particle diamond.

Diamonds Diamonds, also called diamonds, are commonly known as "Jin Gangzuan". The chemical formula is C, octahedral, colorless and transparent without impurities. When it reacts with oxygen, it will also produce carbon dioxide, which belongs to the simple substance of carbon with graphite. The bond angle of diamond crystal is109 28', which is a kind of crystal with excellent physical properties such as superhard, wear resistance, heat sensitivity, heat conductivity, semiconductor and penetration. Known as the "king of hardness", the king of gems. The angle of the diamond crystal is 54 degrees, 44 minutes and 8 seconds. Traditionally, people often call processed products diamonds, while unprocessed products are called diamonds. In China, the name of diamond was first found in Buddhist scriptures. Diamonds are the hardest substance in nature. The best color is colorless, but there are also special colors, such as blue, purple and golden yellow. Diamonds of these colors are rare and precious among diamonds. India is the most famous diamond producer in history. Now many famous diamonds in the world, such as "Mountain of Light", "Regent" and "orlov", all come from India. The output of diamonds is very scarce, and the finished diamonds are usually one billion times the amount mined, so the price is very expensive. Polished diamonds are usually round, rectangular, square, oval, heart-shaped, pear-shaped and olive-pointed. The heaviest diamond in the world is Cullinan, 1905 produced in South Africa, weighing 3 106.3 carats. It was divided into nine small diamonds, one of which, Cullinan 1, known as the "Star of Africa", still ranks first in the world.

Crystal structure: the unit cell is face-centered cubic structure, and each unit cell contains 2 groups of 8 C atoms.

Diamonds Diamonds usually come in yellow, brown, blue, green and pink, but colorless ones are more popular. There are 10 extra-large gem-grade diamonds weighing more than 620 carats (124 grams) in the world, among which the largest Cullinan weighs 3 106 carats (62 1.35 grams) and has a size of 5×6.5×65438. China Changlin diamond, weighing 158.786 carats, was discovered in Linshu county, Shandong province on 1977 and is listed as a world-famous diamond. The main diamond producing areas in the world are Australia, Zaire, Botswana, the former Soviet Union, South Africa, Brazil, Namibia, Ghana, Central Africa, Sierra Leone and China.

It is the tenth hardness grade of Mohs mineral.