The chemical properties of silver are relatively active, and it is easy to react with chemicals containing sulfur and other elements to form compounds of sulfur and silver. After a long time, this compound will slowly form a black silver sulfide film on the surface of silver ornaments, which will initially appear as some tiny spots, and then gradually spread into pieces, commonly known as "silver scales" or "silver mold", which will affect the surface color of silver ornaments.
What is the reason why silver ornaments turn black? As we all know, human sweat contains sulfur, ammonia and other compounds, and some air also contains hydrogen sulfide, nitric oxide and other substances, which will lead to the oxidation of the surface of silver ornaments, and then change color and lose luster.
The oxidation process of silver ornaments is inevitable, but some smooth surfaces of silver ornaments often come into contact with skin or rub against clothes when worn. It doesn't turn black in this case, but it sometimes turns bright. "If the style of silver ornaments is complex and there are many carvings on the surface, then the cracks are more likely to be oxidized. The first discoloration is usually in these places. Simple shape, better oxidation. "
The wearer of silver jewelry should try to take off the silver bracelet when swimming, bathing and washing clothes to slow down the oxidation process. Or when consumers buy silver ornaments, they can choose "925 Silver" (containing 92.5% silver and 7.5% nickel alloy) with stronger oxidation resistance instead of buying Qianzu Silver.
From the above situation, we can know that in order to prevent silver jewelry from blackening, we only need to prevent its oxidation and prohibit contact with substances containing hydrogen sulfide.
I hope I can help you! !