Why is my gold necklace becoming black?

Several reasons could explain why your gold necklace is turning black. Here are the most common culprits:

Tarnishing:

• Alloys: Pure gold itself doesn't tarnish easily, but most gold jewelry is an alloy mixed with other metals like silver or copper. These metals are more prone to tarnishing when exposed to air, moisture, or certain chemicals.
• Sweat and body chemistry: Sweat and body oils contain sulfur compounds that can react with the metals in your necklace, causing it to blacken. This is especially true for lower carat gold (e.g., 14k or 18k) with higher proportions of other metals.
• Chemicals: Household cleaning products, cosmetics, and even chlorine in swimming pools can accelerate tarnishing.

Other possibilities:

• Vermeil or gold-plated jewelry: If your necklace isn't solid gold but rather vermeil (gold plating over another metal) or gold-plated, the base metal underneath might be tarnishing and showing through.
• Fake gold: In rare cases, the necklace might not be real gold at all. Fake gold jewelry can easily tarnish and discolor.

What to do:

• Clean the necklace: Use a mild dish soap and lukewarm water to gently clean the necklace. Avoid harsh chemicals or abrasives.
• Store it properly: Store your necklace in a dry, airtight container away from direct sunlight and harsh chemicals.
• Consider professional cleaning: For stubborn tarnishing, take it to a jeweler for professional cleaning.

Additional tips:

• If you sweat a lot, remove your necklace before exercising or showering.
• Take off your necklace before applying lotions, perfumes, or other cosmetics.
• Consider getting a higher carat gold necklace (e.g., 22k or 24k) with less alloy for better tarnish resistance.

Remember, the best course of action depends on the specific cause of the blackening. If you're unsure, consulting a jeweler can help diagnose the problem and recommend the best solution.