THE MINERAL SCHROCKINGERITE

Chemistry: NaCa₃UO₂SO₄(CO₃)₃F - 10H₂O, Hydrated Sodium Calcium Uranyl Sulfate Carbonate Fluoride.
Class: Carbonates
Uses: As a very insignificant source of uranium and as mineral specimens.
Specimens

Schrockingerite, also spelled schroeckingerite and schrokingerite, is one of the few uranyl carbonate minerals that is found on the mineral markets. Other uranyl carbonates include andersonite, rutherfordine, sharpite, liebigite, swartzite and bayleyite. Schrockingerite in addition to having a uranyl (UO₂) group in its chemistry, has a sulfate ion. Schrockingerite could be classified as a sulfate, but is here classified as a carbonate due to the greater number and therefore greater significance of the carbonate ions. Other sulfate carbonates include susannite, leadhillite, hanksite, macphersonite, wherryite and caledonite. The fact that schrockingerite is a uranyl sulfate carbonate though makes it very rare. Schrockingerite forms as a secondary mineral and is also found on cave and mine walls.

PHYSICAL CHARACTERISTICS:

Color is yellow-green.
Luster is vitreous to pearly.
Transparency: Crystals are transparent to translucent.
Crystal System is triclinic.
Crystal Habits include pseudohexagonal platy crystals and encrustations.
Cleavage is perfect in one direction.
Hardness is 2.5.
Specific Gravity is 2.5 - 2.6 (slightly below average for a translucent mineral)
Streak is slightly off-white.
Other Characteristics Some specimens are fluorescent.
Associated Minerals include clays, gypsum, johannite, andersonite, swartzite and bayleyite and other secondary uranium minerals.
Notable Occurrences include the type locality of Jachymov, Zapadocesky kraj, Czech Republic as well as the Miller Ranch deposit, Kern County, California; Hillside Mine, Yavapai County, Arizona and Lost Creek, Sweetwater, Wyoming, USA; La Soberania Mine, San Isidro, Mendoza, Argentina.
Best Field Indicators: Crystal habit, color, associations, fluorescence and locality.