Mellite is actually an ORGANIC COMPOUND, a bizarre species indeed! It is an Aluminum mellitate (benzene hexacarboxylate) hydrate, a rare secondary mineral in lignite deposits. Crystals of this quality are seldom seen and I think exclusively come from this small mine. My understanding (though I have no proof of this) is that most were mined prior to WWII and few have been found since. These particular specimens feature extremely sharp faces and are quite displayable (which is unusual - often they are broken or included too heavily by matrix) .