If your gold ring turns black, it is likely due to a chemical reaction between the gold and another substance. Here are some possible reasons why your gold ring may be turning black:

1. Contact with other metals: If your gold ring comes into contact with other metals, such as copper or silver, a chemical reaction can occur that causes the gold to turn black. This can happen if you wear other metal jewelry simultaneously or your gold ring rubs against metal objects.
2. Exposure to chemicals: If your gold ring is exposed to chemicals such as chlorine or sulfur, a chemical reaction can occur that causes the gold to turn black. This can happen if you wear your ring while swimming in a chlorinated pool or come into contact with chemicals at work or during household chores.
3. Dirt and grime: If your gold ring is not cleaned regularly, dirt, oils, and other grime can build up on the surface of the gold and cause it to appear black or discolored.
4. Skin oils and sweat: If your skin produces a high amount of fats or sweat, this can react with the gold and cause it to turn black over time.

If your gold ring is turning black, you may be able to restore its appearance by cleaning it with mild soap and warm water. Avoid using harsh chemicals or abrasives, as these can damage the surface of the gold. If cleaning does not restore the appearance of your gold ring, you may need to take it to a professional jeweler for cleaning or repair.