Hello & happy new year! I know these are not valuable, nor rare, I would just like to know what kind of pearls these are. Hopefully somebody can help me. (I feel kinda silly though, I really should know my pearls, since it is my birthstone...) Apparently, the world of pearls has expanded & evolved a bit over the years. I could use a refresher course, so it seems! Oh, there is one other question...how can you tell the difference between a black tahitian pearl and a pearl that has been dyed, without unstringing it? The knots are very snug, so I really cannot see into the drill hole! Thanks!