Carat (Ct) is the unit of mass (weight) of gemstones. Now it is determined that 1 carat is equal to 0.2g or 200mg .. One carat is divided into 100 minute, such as 50 minutes or 0.5 carat, which is used to calculate smaller gemstones.

The crystal plane of water crystallization is glass luster, while its conchoidal fracture is oily luster; The hardness is 7, the specific gravity is 66, and it has compressive and optical properties. Crystal has a wide range of uses, mainly used as necklace beads in handmade and jewelry, as well as some small pendants and ornaments. Crystal is mainly produced in Brazil and Uruguay, and China is mainly produced in Yangjiaoling in Hainan and Donghai in Jiangsu.

Jinlong Jindian is one of the few jewelry brands with mines in China. The largest gold reserves are not on land, but in the ocean, where there are as many as 20 million tons of gold. The largest gold reserve is 8 135 tons in the United States, and China ranks fourth 1846 tons.