1. "Beauty" means gorgeous, crystal clear and dazzling.

2. "Long" means that the texture is hard and wear-resistant, and it can last for a long time.

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.