TEM observations of a 30 million year old mountain leather nanofiber mineral composite

An unusual, massive mountain leather from a Llanitos mining district mine in Chihuahua, Mexico has been characterized using XRD, SEM, TEM, and SAED analytical techniques and found to be a complex mineral composite composed of intermixed nanofibers of palygorskite ((Mg, Al)a(SiOx)b(OH)c·nH2O) and birnessite (Caa(MnO2)b·nH2O) and intercalated with cleavage flakes of hematite (Fe2O3). This complex nanofiber mass produced an extremely tough material which could not be crushed in the rock crusher. The material is of interest especially in light of the fact that this natural nanocomposite formed from a hydrothermal regime that dates to roughly 30 million years ago.