Many people wear them for style statement but some do it to show their affiliation to a particular faith, for example a Christian might wear bejeweled cross to show his faith in Jesus Christ. A lot of people also wear such ornaments as their birthstones or as medallions for different organizations.
While selecting one, there can be two ways to look. You can first look at the gemstone being used and then design of the chain and attachment or you can look for the design of the chain and then notice the gemstone. The person’s body size makes a big difference on how the pendant (additional info) would look on him, so it should be neither too small nor too large in proportion to the size of the person. A small, intricate design may not look good on a larger person similarly a large pendant may look somewhat overwhelming on a smaller person.
If a person plans to buy a pendant just to make style statement he should think about the dresses that can be worn with it. Like a v-neck dress or top is perfect with most of the pendants as they tends to pull the chain down into a V shape which matches the neckline of the clothing. A pendant with thicker chain suits best with dresses having rounded collars as it gives a more rounded look to complement the neckline of the dress.