Sources from which information derived from
http://www.mindat.org/min-3727.html
http://webmineral.com/data/Sphalerite.shtml#.UyoXj69OWYc
http://earthsci.org/mineral/rockmin/mineral/mineral_i_d.html
http://www.minerals.net/mineral/sphalerite.aspx
Pellant, Chris. Copyright 1992,2002 Smithsonian Handbooks: Rocks and Minerals
Page 55
http://webmineral.com/data/Sphalerite.shtml#.UyoXj69OWYc
http://earthsci.org/mineral/rockmin/mineral/mineral_i_d.html
http://www.minerals.net/mineral/sphalerite.aspx
Pellant, Chris. Copyright 1992,2002 Smithsonian Handbooks: Rocks and Minerals
Page 55