Color: Platteville - Galena chert ranges from gray to light tones of brown. Mottles and swirls are present.  White specks may be present which are fossil fragments.  Small flat vugs may be present.

Texture:  Primarily fine grained, though courses grain does occur

Luster: Dull to waxy

Silica Fabrics / Fossils: Fossils are present including sponge spicules, brachiopods, bryozoans, and corals.

Patina:

Heat Treatment:  Heat treatment changes the color to reddish or reddish brown and increases the luster.

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Platteville-Galena Chert is associated with the Platteville Dolomite of northern Illinois and southern Wisconsin.  Primary outcroppings in Decorah and Canoe, Winneshiek County,  Iowa.  Has been reported into southeastern Minnesota, southwestern Wisconsin, and northwestern Illinois.