Craigslist is an incredible place to sell a diamond or engagement ring. People prefer local deals and are often looking for good bargains, so you might have your best luck here. However, when selling your jewelry here, please be patient; it might take time for the right buyer to show up.
When you sell on Craigslist, please prioritize your safety and watch out for scammers. If someone suggests an online transaction on Craigslist, it's likely a scam, so it's best to avoid it. Also, please ensure you meet potential buyers in a safe location, such as a police station or a trusted jeweler.
If you agree to meet at a jewelry store, ensure it is a reputable establishment. Some jewelers may try to discourage potential buyers from acquiring your stone in the hope of selling them their own goods.
Con
The biggest con is that it might take months to find the right buyer, especially if you need the money urgently.