1. Diamond: Known as the "King of Gems", it is one of the hardest natural substances in the world. Diamond has become one of the most popular gems because of its high hardness, strong durability and beautiful light.

2. Ruby: It is called "pigeon's blood" because of its bright color. It is a high-purity gem and is often used at many banquets.

3. Sapphire: The blue color of sapphire is mainly caused by a small amount of titanium and iron impurities. Sapphire is not limited to blue, and there are three rare and precious varieties: cornflower sapphire, royal sapphire and starlight sapphire.

4. Emerald: Emerald is called the king of emeralds and is one of the four precious stones. The appearance is emerald green, slightly yellow or blue, transparent to translucent, usually with glass luster.

5. Opal: Opal is a gem with special optical effects. Its colorful colors are often used as high-grade jewelry.