2 Answers

Explained here...http://www.ehow.com/how_6002610_spot-differences-nickel-sterling-silver.html

There some steps by that you may check the silver jewelry

Check the interior of the silver piece for the marking ".925" engraved on any component of the metal.

 Notice if the metal is wearing down, exposing a darker, dull metal. This indicates that the metal is not sterling silver, but is nickel that has been plated with silver.

Put the metal under a strong light and take notice of its reflective quality.

Rub the metal with a cloth. While sterling silver and nickel silver both tarnish, nickel silver can be shined fairly easily with a cloth alone.

For know more you may ask any jewelry expert.  But buying jewelry from a trusted brand will be better for shop. As like I like to shop any kinds of bracelet as ordered it from a trusted store as jewelrybytali.com