Color:  Tongue River Silicified Sediment is finely mottled and ranges from a grayish brown to a light olive brown or yellowish brown or red sediment, pseudoquartzite, or arenaceous chert.

Texture:  Course to medium fine grain

Luster: Dull with vitreous quartz inclusions giving a "silty" appearance

Translucency:   Opaque

Silica Fabrics / Fossils:

Patina: Tan to dark brown or white

Heat Treatment:  Heat treatment produces red or maroon hues, increases the luster to a silky appearance, and increases flaking quality.

Knapping:  Very difficult to work with and poor flaking quality in natural state.  Heat treatment improves the flaking quality to marginal.

Notes:  Taylor Bed Silcrete is more abundant and has many overlapping characteristics of Tongue River Silica.  It has been noted that many artifacts identified as Tongue River Silica are actually Taylor Bed Silcrete.

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Tongue River Silicified Sediment is associated with the Slope / Bullion Creek formation.  Primary sources are located in Slope, Bownam, Adams, Grant, and Morton counties, North Dakota.  Has been reported in glacial drift into Iowa.  This is considered an exotic or non-local material.