Color: Girardeau Black chert is a dark bluish black chert.

Texture: 

Luster:

Silica Fabrics / Fossils:

Patina:

Heat Treatment:   

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Girardeau Black Chert is associated with the Girardeau Limestone Formation, Maquoketa Group.  Primary outcropping occur in Cape Girardeau County, Missouri and into Illinois.