Precious metals refer to metals with higher prices in the financial market, which are usually favored because of their preciousness, scarcity and special uses in industry, investment, jewelry and so on. Common precious metals include:

1. Gold: Gold is one of the most famous and widely invested precious metals. It is used as a safe-haven asset and also widely used in jewelry, industry and electronic products.

2. Silver: Silver is another common precious metal, which is usually regarded as a safe-haven asset by investors together with gold. Silver is also widely used in industry, including electronic equipment and solar panels.

3. Platinum: Platinum is used in manufacturing automotive catalytic converters, chemical industry and medical equipment. It is also an important jewelry material and is considered as a high-end precious metal.

4. Palladium: Palladium, similar to platinum, is mainly used for manufacturing automotive catalytic converters, and also has certain applications in the electronics industry and jewelry industry.

These precious metals are often used by investors to diversify their portfolios because they usually show relatively stable characteristics in the face of market fluctuations and economic uncertainties. Investors can participate in the precious metal market by purchasing physical precious metals, gold and silver ETFs (exchange traded funds) and precious metal futures. However, it should be noted that the precious metal market also involves risks, and sufficient research and risk assessment should be carried out before investment.