Even more than for other jewellery, it is very hard to categorize necklaces and pendants. This starts with the type of the chain or necklace - a simple leather cord might be used, a necklace made from fine stainless steel strands (even partly gold-plated), one of the various chain types like anchor chain, belcher chain, curb chain, king chain etc.
However, even for a simple pearl necklace, some issues should be considered. Obviously, the most simple way is to just thread the pearls onto a length of pearl silk - this is easy and is done pretty fast. There is a disadvantage, though - if the thread snaps, all pearls fall down. This is why more precious pearls, stones and other materials is usually not just threaded but knotted. When a knotted necklace snaps, only one pearl might fall. Additionally, threaded necklaces (and knotted ones as well) should be inspected for wear once in a while - I will gladly do this for you and can also offer you appropriate repair optionsif necessary.
Maybe even more options are available for pendants. Nearly everything can be worn as a pendant - from the classical solitaire brilliant-cut diamond to the shell you once found on the beach. All kinds of precious metals can be used for fitting or for the pendant itself - also Mokume Gane. I will help you in designing your personal pendant as well.