Tudengite

Tudengite is the name given in some mineralogical sources to a proposed mineral species. It is not listed as a valid mineral in major databases such as Mindat.org or Webmineral, and there is no widely accepted chemical formula or crystallography. Because of the lack of a formal description and type specimen, its status remains uncertain.

History and naming: The name has appeared in older or obscure lithology records; its etymology appears to follow the common practice of naming minerals after a locality or individual, but no definitive source confirms the origin. Some authors have treated tudengite as a possible misidentified sample of a known phosphate or silicate; others have left it as a nomen nudum.

Properties and occurrence: No verified measurements are available; there are no reliable data for hardness, gravity, cleavage, color, or crystal system. Consequently, there are no confirmed occurrences or locality data.

Status and outlook: If a complete peer-reviewed description with a type specimen is published and accepted by the International Mineralogical Association, tudengite could be recognized or ruled as invalid or as a synonym. Until then, tudengite remains an obscure or dubious name in mineralogical literature.