Bronze
There is an interesting cold knowledge, which may not be the same as everyone's cognition - pure copper is a soft metal, the surface is reddish orange with metallic luster when it is just cut, and the element is purple-red.
What we call "bronze" is made of alloy copper. For example, the copper hot pot that old Beijing likes to use is industrial pure copper, but it is actually an alloy; and the proportion of copper in the brass hot pot material will be relatively low, which is a copper-zinc alloy. The picture below is the small teaspoon I use, also of brass.
Friends who like Tibetan culture also often come into contact with "Lima copper", for example, I have an old scripture buckle changed by the pendant of Lima copper.
Historically, the real Lima copper is mixed with gold, silver, steel, tin, lead, mercury, five-color glass surface, etc. in copper, so it will flash a colorful halo on the color of the finished product.
Beijing is already very cold, the mountains are snowing again, everyone pay attention to keep warm.