The IRS views gold is as a capital asset, with any gains taxed as income.
What this means for selling gold jewelry is that if you sell the jewelry for more than was paid for it, you should count the difference between the two as taxable income. Capital gains on collectibles, including gold jewelry, are taxed at 28%.
For example, if a bracelet was bought for $100 and sold for $200, you have made a gain of $100. Tax wold therefore be $28.
In reality, it’s unlikely that the amount you receive will be more than you paid for it, so you shouldn’t have to worry about this.