4mm Round Ruby Stud Earrings in Sterling Silver .60ct tw Gemstone : Ruby Gemstone Size: 4mm = .60cttw Mounting: sterling-silver All purchases from SuperJeweler come with The SuperJeweler Lifetime Guarantee. Your SuperJeweler jewelry purchase includes a lifetime guarantee against the loss of side stones or damage to the jewelry's setting or center stone. It also includes a one-year replacement guarantee against the loss of your jewelry's center stone.