Minerals found in Wisconsin
Here are some of Wisconsin’s more common geological offerings.
Galena {Lead Sulfide}:
PbS is Wisconsin’s state mineral.
It is an important source of lead and historically lots of galena was mined in southwestern Wisconsin.
It usually forms silver cubes that are very heavy.
Calcite {Calcium Carbonate}:
CaCO3 is a common mineral that forms clear to whitish crystals that break into rhombohedrons when freshly broken (they look like small angled boxes).
An easy way to determine if you have calcite is to put a small amount of vinegar on your sample.
Calcium carbonate will react with this dilute acid and will fizz.
Quartz {Silica}:
SiO2 is one of the most common minerals on earth.
It comes in many different colors including purple (amethyst), yellow-brown (citrine), gray to black (smoky quartz), pink (rose), and clear.
Crystals of quartz are six sided, but they fracture randomly when broken.
SOURCE: The Department of Geology & Geophysics
The University of Wisconsin - Madison
http://www.geology.wisc.edu