whoa.. you opened them already? the "rocks" are normal.. thats the embryo or w/e its called.. You didnt open them all did you?
put them in a cup of water.. if they sink, they should sprout.. they will all prolly sink as they have been germing fior a few days.. If they do sink, imediately put them in some wet paper towels ( wetter than u tried before ) and place them in a baggie and seal it and place it on top of a tshirt on top of the heat pad.. If u put the baggie directly on the pad it will get too hot even on low.. Some seeds needs more moisture and heat than others. try the heat pad and more moisture in the baggie.