Hypogene ba-rich todorokite
and associated nanometric native silver in the san miguel tenango mining area, Zacatlan, Puebla, Mexico.
"Pyrolusite" is a term used locally to describe black manganese oxide dendrites at Hunting Hill, but they have never been precisely characterized, and therefore it is unclear if they are pyrolusite or another similar manganese mineral such as romanechite or todorokite
Unlike the products of previous attempts, the synthetic todorokite retains its basic properties at temperatures up to 500 degrees C.
Todorokite captured the attention of chemists because of its large pores and ability to selectively soak up and then release positively charged cations, much as zeolites do (SN: 8/3/91, p.77).
Todorokite (Mn,Ca,Mg)[Mn.sub.3][O.sub.7] * [H.sub.2]O
Black coatings of todorokite are common throughout the silica carbonate rocks at the upper and lower workings.
Todorokite is one of the non-crystallized manganese oxides which form "wad" at Val Graveglia (Antofilli et al., 1983).
George Rossman later determined the black mineral to be some of the purest todorokite
Oxides & Hydroxides Anatase Birnessite Doyleite Franconite Gibbsite Goethite Hematite Hochelagaite Lueshite Todorokite Woodruffite VUK3
Todorokite is rarely found in altered miarolitic cavities as thin, opaque, dark brown to black dendritic deposits and crusts.
: a new family of naturally occurring manganese oxides," Science, vol.