The words "925" or "STERLING" may not necessarily appear on an antique sterling silver necklace. While it is usual practice to hallmark items to show their silver content, older or antique pieces may gradually lose their logo due to wear. Additionally, historically, some locations or artists might have yet to label their jewellery consistently. The necklace may still be sterling silver even if there are no marks on it. In these situations, speaking with a qualified jeweller or having a silver purity test can assist in validating its authenticity since they can examine the piece's construction and craftsmanship to verify whether it is made of real sterling silver.