Color:  Elwood - Joliet chert ranges from white to gray

Texture: Medium to fine grain

Luster: Dull

Silica Fabrics / Fossils:  In Elwood Chert, brachiopods are common.  Both Joliet and Elwood chert sponge spicules, brachiopods, brazoans, corals, and crinoid columnals may be present.

Patina:

Heat Treatment:  Heat treatment brings a slight pinkish hue and increases the luster.

Knapping: 

Note:  There are many overlapping characteristics between Burlington, Elwood, and Jolie cherts making identification between these cherts difficult.
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Elwood Chert is named for outcroppings found in Elwood Il.  Joliet Chert is named for outcroppings located in Joliet Il.  Elwood Chert is associated with the Elwood formation found in the Des Plaines River Valley.  Joliet Chert is associated with the Joliet formation found in levels above the Elwood formation.  They are both associated with northeastern Illinois and into Wisconsin and Iowa.