Color:  Harmilda Chert has a semi-transparent region and a opaque region.  The Semi-translucent portion ranges from tan to gray and the opaque regions range from white to gray.

Texture:  The texture varies depending on the color of the chert.  The semi-translucent tan to gray regions tend to have medium to fine grain while the opaque white to gray regions tend to have a course to medium grain.

Luster: The semi-transparent regions have a waxy luster and the opaque regions have a dull luster

Silica Fabrics / Fossils: Relatively few fossils are present in Harmilda Chart.  The limited number is comprised of sponge spicules in the semi-translucent regions and crinoid casts in the opaque regions.

Patina:

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

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Harmila Chert is associated with the Siluriam System of  DuPage County, Illinois.