Magma can cool to form an igneous rock either on the surface of the Earth-in which case it produces a volcanic or extrusive igneous rock, or beneath the surface of the Earth, - in which case it produces a plutonic or intrusive igneous rock.
Applying for an EIN number is free of charge and can be completed online. I've linked the IRS area below where you'll learn more about the application process. http://www.irs.gov/businesses/small/arti...
The EIN is not your tax-exempt number. That term generally refers to a number assigned by a state agency that identifies organizations as exempt from state sales and use taxes. You should contact your state revenue department for additional information about tax-exempt numbers.