2. As a precious metal, gold has good physical properties. "Real gold is not afraid of fire" means that gold has high chemical stability and is not easy to react with other substances, so there is no need to worry about oxidation and discoloration. Even in the molten state, it will not be oxidized and discolored, and it will still glow after cooling. High density and heavy hand feel. Good toughness and ductility, good electrical conductivity. Pure gold is bright yellow, but its color changes greatly when mixed with other metals. For example, the gold-copper alloy is dark red, and the silver-containing alloy is pale yellow or grayish white. Gold is easily ground into powder, which is why gold is scattered in nature. Pure gold jewelry is also easy to wear, reducing weight.
A consumer group refers to a collective with consumption behavior and one or more of the same characteristics or relationships. For example, consumers have similar income levels, the same shopping interests, or the same age, or the same job nature and occupation. In some works, they are called the consumer class. The main basis for dividing the consumption class is to refer to the social class division standard. Consumer class and social class are not exactly the same. For example, consumers of professional goods can form a consumer class (generally called consumer group), and it is difficult for social class to find equivalent concepts. Therefore, the concept of consumer class has great limitations.