@book{119375,
	author = {Schumann, Walter,  and Bradshaw, R. },
	title = {Handbook of rocks, minerals, and gemstones /},
	publisher = {Houghton Mifflin Company,},
	year = {c1993.},
	address = {Boston :},
	note = {Spine title: Rocks, minerals & gemstones},
	url = {http://www.loc.gov/catdir/description/hm021/92028505.html}
}