- Chemical Formula: (U4+,Ca)(Ti,Fe3+)2O6 , Uranium
Calcium Titanium Iron Oxide
- Class: Oxides and Hydroxides
- Uses: a major ore of uranium and radium, a source of helium and as a mineral specimen
is a highly radioactive and interesting mineral. It is named after Dr. John
Casper Branner (1850-1922), formerly a Professor of Geology and President of
Brannerite is found in the same settings as gold,
including placers, quartz veins, and in granite pematities. It may be black, but
is more often found in shades of yellow to brown to green. It forms only tiny
crystals, which may be vitreous. Thin sections are translucent, transmitting a
yellow-green light. It may fluoresce yellow under short-wave ultra-violet light.
It is one end of a series called the Brannerite-Thorutite series.
is brown in shades of yellow to green; may be yellow or yellow-green in thin
- Luster is vitreous, sometimes reported as resinous or dull.
- Transparency crystals are translucent.
- Crystal System is monoclinic, 2/m
- Crystal Habit is prismatic.
- Cleavage is absent.
- Fracture is conchoidal.
- Hardness is 4.5 - 5.5
- Specific Gravity is 5.2
- Streak is dark greenish-brown to yellowish-brown.
- Associated Minerals include gold.
- Other Characteristics: radioactive, fluorescent yellow
- Notable Occurences include Ontario, Canada; Colorado, Stanley Basin,
Wyoming, and Custer County, Idaho, USA
(the type locality).
- Best Field Indicators are luster, color, radioactivity and streak.