It was accidentally given to him as a donation, but he didn't try to cash in.
United Press International has a story about Billy Ray Harris, a homeless man in Kansas City who got a little more charity than he’s used to.
On Feb. 8, a woman named Sarah Darling stopped to give him some change, dumping the contents of her coin purse into his cup. But for some reason – she says her rings were bothering her – she had placed a ring with a sizable diamond in the purse, and unknowingly deposited it into the cup, too.
Harris noticed about an hour later, and immediately realized it was quite valuable. But, he told UPI, he never considered selling it. He just held onto it, and the next day Darling came back.
She asked if he remembered her, and honestly, he didn’t – you see a lot of people when you’re sitting on the sidewalk all day. But when she mentioned losing something valuable, he realized it was hers and returned it. As thanks, she gave him all the cash she had on her. (The story doesn’t say how much that was.)
Harris told UPI, “My grandfather was a reverend. He raised me from the time I was six months old and thank the good Lord, it’s a blessing, but I do still have some character.”