Color:  There are two variations of Cedar Valley Chert.  The first is opaque and ranges in color from yellowish brown to dark brown or an ocher color with mottling.  This form is often called Root River Jasper.  The second variation is translucent ranging from a light to medium brown.  It commonly looks like a quartzite and is often referred to as Cedar Valley chert.

Texture:  Fine grain

Luster: Dull to waxy

Silica Fabrics / Fossils:

Patina: Colors of off white, yellow, tan, brown, gray, blue gray, pink, or red.  These colors could be a result of heat treatment.

Heat Treatment:  Heat treatment produces colors or reds to cranberry red or brown.  The luster increases to a waxy or vitreous luster.

Knapping:  Opaque material has a better flaking quality, Translucent material is slightly more difficult to work with.  Heat treatment improves the flaking quality. 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Cedar Valley Chert is associated with the Cedar Valley Formation of the Rapid Member.  It is found from the Root River, Mower County, Minnesota to the confluence of the Mississippi / Illinois Rivers.  Primary sources have been reported in Fillmore County, Minnesota.   It has been found in cobbles down the Mississippi River.