So i was thinking about the prime matter of this work...It is contained within ALL the 4 elements and we need it to start the work.The only common thing i can come up with that connects fire,air and water is Oxygen.As for the earth,there are quite a lot of oxides within it which means they bring oxygen within them.So,the first matter(since it has to be a rock/ore/mineral) will probably have to be an oxide or something that can turn into an oxide somehow.Here is a picture of this ore but i cant tell much about it from the pic
http://postimg.org/image/dt0ywuso1/
The comments of the author that are linked to this picture are:
"This is a sample of the First Matter, a sample of this ore which contains in its breast the Sun and Moon of our Philosophers, as well as the Salt in an infinitesimal dose. Hermes, Paracelsus, Albert the Great, J.-B. Porta, etc., have called it cinnabar, either designating it overtly by its name or describing the method of making it artificially. Certain reader believed that the Master Kamala-Jnana refuted this ore categorically. This is not true at all; Kamala-Jnana simply said it should not be treated like the industrial ore. It is thus that it is analogous but not equal, similar but not identical."
Any ideas?