A 6 string mandolin is one of the different kinds of mandolin. A mandolin is a musical instrument of the lute family. Aside from its differences on the number of strings, mandolins also have different back shapes that causes different types of sound. Different country or continent has their own version of mandolin that makes their music unique.
If you would like to start playing mandolin, check what kind of music you would like to play so you can get yourself the right type of mandolin. And before buying, check the brand first. Make sure that the strings are also of good quality. Everything contributes to make the sound at its best.