A. High-grade gems such as diamonds, rubies, sapphires and emeralds (variable stones and cat's eyes).
B, low-grade gems such as tourmaline, beryl, garnet, spinel, crystal, etc.
C, rare gems such as taffeta, blue cone, etc. The output is scarce, only for laboratory collection and display. A few beautiful, durable and rare mineral aggregates with scientific and technological value produced in nature are amorphous. According to hardness and technological characteristics, it is divided into:
A. The Mohs hardness of high-grade jade is 6.5-7. Internationally recognized high-grade jade is jadeite and nephrite. (commonly known as jade and hetian jade)
B, the Mohs hardness of middle and low grade jadeite is 5-6. Such as agate, lapis lazuli, serpentine (jade) and so on.
C. The Mohs hardness of stone carvings is less than 4, such as Yin Zhangshi, inkstone and ornamental stones. Some can be of high value, such as Tian Huangshi and bloodstone. All or part of the materials produced or manufactured by people and used as jewelry and decorations are collectively referred to as artificial products. Including synthetic gemstones, artificial gem, divided gemstones and reconstructed gemstones.
1, synthetic gem. Completely or partially artificially made crystals or amorphous bodies with known counterparts in nature, their physical properties, chemical composition and crystal structure are basically the same as those of the corresponding natural gemstones. Such as synthetic crystals.
2. artificial gem. Man-made crystals and amorphous bodies have no known counterparts in nature and are called artificial gem. Such as artificial yttrium aluminum garnet and artificial strontium titanate.
3. Assemble gems. Jewelry and jade, which is composed of two or more pieces of materials and gives people an overall impression, is called split stone, or split stone for short. Like assembling opals.
4. Recreate gems. By artificial means, the fragments or chips of natural jewelry and jade are melted and pressed into jewelry and jade with overall appearance. Such as recycling amber and turquoise.