You are not able to keep it in your inventory?
Then please check the "System" window if it contains a message about the reason. Is your character (fresh from start) too weak to hold even one molten piece? Or do you drop it onto a non-empty slot?
Try to get a Game Master who can guide you here. The best way may be in IRC: irc://chat.freenode.net/planeshift-gmtalk (unfortunately, this board software does not support clickable IRC URLs).
Call the names of members with "Ops" attribute, and ask if they can support you in the tutorial. You may have to tell them your tutorial instance number (enter "/pos" in the game message window and look in the "System" tab).