• Chemistry:Pb(UO2)(TeO3)2, Lead Uranyl Tellurite
  • Class: Sulfates
  • Subclass: Tellurites
  • Uses: Only as mineral specimens.
  • Specimens

Moctezumite is a very rare tellurium mineral discovered in 1965 by Richard Gaines (1917 - 1999), an American minerologist. Its type locality is the Moctezuma Mine, Moctezuma, Sonora, Mexico, hence the name. The Moctezuma Mine is famous for rare telllurium minerals. Other minerals from here include: bambollaite, cliffordite, denningite, emmonsite, spiroffite, tellurium and zemannite. Not only is moctezumite a tellurium mineral, it is also a uranium mineral. The uranium ion in moctezumite is part of a group of ions called the uranyl ion group. The uranyl ion group, UO2, is unusual in that it is a positively charged (+2) ion group. Most ionic groups, especially those that contain oxygen are negatively charged such as the sulfate ion group, SO4-2; carbonate ion group, CO3-2; borate ion group, BO3-3; phosphate ion group, PO4-3; tellurite ion group, TeO3-2 and the silicate ion group, SiO4-4. Another positively charged ion group is the ammonium ion group, NH4+1, found in only a few minerals. Remember, moctezumite is a radioactive mineral and should be stored away from minerals that are affected by radioactivity and of course human exposure should be limited.


  • Color is orange to brownish orange.
  • Luster is vitreous to adamantine.
  • Transparency: Crystals are translucent.
  • Crystal System is monoclinic; 2/m.
  • Crystal Habits include small granular crystals.
  • Cleavage is good in one direction.
  • Hardness is 3.
  • Specific Gravity is approximately 5.7 (very heavy for translucent minerals).
  • Streak is pale orange.
  • Other Characteristics: Specimens are radioactive and index of refraction is very high at 2.11 to 2.12.
  • Associated Minerals include various other tellurium minerals such bambollaite, cliffordite, denningite, emmonsite, spiroffite, tellurium, zemannite and other tellurates and tellurites.
  • Notable Occurrences are limited to the type locality of Moctezuma Mine, Moctezuma, Sonora, Mexico.
  • Best Field Indicators are locality, high density, color, radioactivity and cleavage.
Popular Members of the Sulfates Class


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