For a gift, I got some Ethiopian opals from online, and sanded/ polished them into some earring studs. They looked great at first. However, one of the earrings quickly got cloudy. She's worn them 24/7, (including showers and to bed), but I didn't expect the stones to wear out so quickly.

I'd appreciate any tips to keep the earrings in good shape, or suggestions for more durable stones I could make into daily-wear earrings. Thank you!