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,
hence the name.
The Moctezuma Mine is famous for rare telllurium minerals.
Other minerals from here include:
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
the silicate ion group, SiO4-4.
Another positively charged ion group is the ammonium ion group,
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.
THE PHYSICAL CHARACTERISTICS:
- 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
- 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
tellurates and tellurites.
- Notable Occurrences are limited to the type locality of Moctezuma Mine, Moctezuma, Sonora,
- Best Field Indicators are locality, high density, color, radioactivity and cleavage.