Well what do you want the amulet to be used for? Amber is used for protection and enhancing magick. If that is what you want then yes, amber would be a good choice. As far as its shape it really doesn't matter. Whatever suits your fancy as they say.
thanks for the tip. i love amber and i want to give an amber amulet to my friend for protection, (she has a little fight with her family i don't know what i could help her, so i wanted to give her an amber amulet)