Color:  Spergen Chert is commonly banded or mottled and ranges in color from a very light gray to a gray or brownish gray, and a pale yellow to a tan.

Texture:

Luster:

Silica Fabrics / Fossils:

Patina:

Heat Treatment:  Heat treatment produces reds in the tans of the chert.

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Spergen Chert is associated with the Spergen Formation Iowa.  Primary outcroppings occur in Henry, Jefferson, and Van Buren counties, Iowa.