I just want to laugh at the math. 1 for $4.71 or 2 for $12.48? Haha

Price has gone up! Now it’s $5.49 with a $0.25 discount for 1 and $21.99 for two! :)

Can it be used for sterling silver?

For Sterling Silver, it’s best to use a special cloth designed for it, such as: connoisseurs Silver Polishing Cloth Jewelry Cleaner - Transform Your Silver Jewelry from Dull to Dazzling They also make smaller wipes, which I use first on jewelry that is heavily tarnished. If you have larger silver pieces, such as silverware, bowls, etc, it’s best to start with their liquid tarnish remover.

Is this OK for Moissanite?

Yes, it works really well on moissanite! Mine got the dreaded oil slick a few months ago, and this was the only cleaner that removed it completely. I tried a variety of cleaners and recommendations from Charles and Colvard, and this was the only one that actually did the job! It looks just as sparkly as the day I got it now.

Would this work on opals?

No—as other answers state. For opals, turquoise, and organic stones (pearls, corals, etc), you need a special polishing cloth, such as: Hagerty Fine Stones Cloth Jewellery Cleaning Cloth 36 x 30 cm I Impregnated Cotton Jewellery Cloth I Efficient Jewellery polishing Cloth for Jewellery with Emeralds Pearls opals Corals Turquoise The above cloth is safe and effective for such stones.