Crystal is a very ancient gem. In the ancient works of “Guang Ya” and other works in China, there are many kinds of crystals such as “water jade”, “water essence”, “jade crystal”, “thousand-year ice” และ “shining stone”. ชื่อ, the aliases such as “water essence” และ “thousand-year ice” are obviously due to the lack of a correct understanding of the composition and cause of crystal.
The chemical composition of crystal is silica. It is a crystal of the quartz group minerals that is transparent like water (although crystals are not transparent, they can only be called quartz crystals). If it is purple, brown or black due to impurities, they are called amethyst, citrine and smoky crystal respectively; special varieties with needle-like or fibrous mineral inclusions inside are called “fajing”.
There are many forms of crystals, but the most common one is a hexagonal cylinder composed of a hexagonal column and a hexagonal cone. The most common crystallization habits of crystals are columnar, short columnar, biconical, เป็นต้น: There are often parallel horizontal stripes on the cylindrical surface of the crystal.
The color of crystal varies widely, including light yellow, สีน้ำตาล, smoky gray, purple and black, เป็นต้น, and colorless and transparent are common.
Important producing countries for amethyst are Brazil, Uruguay, Russia’s Ural Mountains, อินเดีย, Madagascar, the United States and Mexico. These countries also produce colorless and transparent crystals.
Amethyst is produced in China’s Shanxi, Shandong, Xinjiang, Inner Mongolia, Guangdong and other provinces. There are more provinces producing colorless crystals, but the most famous are the following two:
Yangjiaoling in Hainan Province: In an area of only 0.2 square kilometers and a depth of 150 meters, nearly 100 tons of piezoelectric crystals are produced, and more than 2000 tons of smelted crystals are produced. It is known as the world’s richest mining area for high-quality crystals.
Donghai County, Jiangsu Province: ใน 1958, a Chinese “Crystal King” with a length of 1.7m, a short diameter of 1.2m, and a weight of 3.5t was produced. ใน 1973, 1978 และ 1983, a huge one with a weight of 1 to 3t was mined several times. Crystal is known as the “Hometown of Crystal”. It is proved that the crystal reserves reach several million tons within a range of hundreds of square kilometers. ในอดีตที่ผ่านมา 20 ปี, the country’s annual crystal purchases in Donghai County accounted for about half of the national purchases.
Crystals come in many colors and can be processed into various jewelry such as rings, สร้อยคอ, จี้, and bracelets.