Color:  Rapid Chert ranges in color from a medium gray to a olive gray or yellowish gray, grayish orange, or pale brown with darker fossil inclusions.

Texture: 

Luster:

Silica Fabrics / Fossils: Bryozoa, crinoids columns, brachiopods, and corals

Patina:

Heat Treatment:  Heat treatment produced pink and purplish colorations and occasionally increases the luster. 

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Rapid Chert is associated with the Rapid Member, Cedar Valley Formation, Lower Cedar Valley Group.  Primary outcroppings occur in the Lake Macbride region and in the Coralville Reservoir Basin.  Outcroppings occur in Buchanan, Howard, and Johnson counties, Iowa.