Color:  Bowman Chert is porcelain white to light brown or light gray with brown chalcedony inclusions.

Texture:  Medium to fine grain

Luster: Dull to porcellaneous

Silica Fabrics / Fossils:

Patina:

Heat Treatment: 

Knapping: 

Notes:  Though this is referred to as chert, it is silicified freshwater marl (mixture of calcite and clay occurring in nearly equal amounts) or porcellanite (mixture of silica and clay with some calcite present). 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Bowman Chert has primary outcroppings aroun Bowman Lake in Glacier National Park in Montana