Getting a necklace to display while using a skin?

I am very new. My SL sim is wearing a skin made by some one else. I bought a diamond necklace that sparkles and I can't get it to show up when wearing it. Can someone direct me on what I need to do to get it to show? Do I need a different type of skin? Thanks in advance!

Welcome, Avalon! Do you mean that you can't see the necklace when you wear it, or that the 'sparkle' effect doesn't show? If you can't see it, it may be attached so that it's inside your av; in that case, try a different attachment point (such as the spine) and use edit to reposition the necklace. If the 'sparkle' effect isn't showing, you might check to see if the item has a 'bling on/bling off' type of function; many jewelry items like this are scripted so that the sparkle can be turned on and off with a simple command. If that's the case, there should be a notecard included to explain the command, or you could always ask the creator what the command is. Hope this helps!