Jewelry must have the following characteristics:
1, "beauty", that is, gorgeous, crystal clear and dazzling.
If a gem is not beautiful, it can't be a gem. This kind of beauty is either colorful, transparent and clean, or has special optical effects (such as cat's eye, color change, night light, etc.). ), or have special patterns (such as chrysanthemum stone, agate, plum blossom jade, etc. For example, diamonds with few defects can be polished into precious diamonds, while those with poor transparency, many defects and black color can only be used as industrial raw materials.
2, "long", that is, the texture is hard and wear-resistant, and it can last for a long time.
Because of its high value, people must expect it to be durable, valuable and even heritable. One of the reasons why diamond is the most expensive gem is that it is the hardest in the world and is not afraid of corrosion. Therefore, most of the high-value gems in the world are silicate minerals with high hardness and corrosion resistance (such as jadeite), a few oxides (such as rubies and sapphires) and elemental minerals (such as diamonds), while the soft and corrosive gems (such as xiuyan jade and Southern Jade) are of higher value. But there are also a few precious stones that are not included, such as opals and pearls.
3. "sparse", that is, the output is small.
Rare things are precious. Emerald, which is extremely rare in the world, is worth tens of thousands of dollars per carat (0.2 g) because of its superior quality, while some beautiful and "enduring" gems (such as amethyst) have always been low in price because of their large output and easy mining. Some ordinary rocks, after pondering, also have the characteristics of beauty and durability, but they cannot become a member of the gem family. The reason is that things that are easy to get will be cheap.