Color:  Hopkinton Chert is translucent light gray with white opaque mottling.

Texture: 

Luster:

Translucency:  Translucent and opaque

Silica Fabrics / Fossils: Small crinoids

Patina:

Heat Treatment:  Heat treatment produces pink hues and increases the luster.

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Hopkinton Chert is associated with the Hopkinton Formation of northeastern to east central Iowa.  Primary outcroppings in Dubuque, Clayton, Delaware, and Jones counties, Iowa.