Knife River Flint
By Dick Eckles, Editor, NAS 

The beautiful artifact in the photograph is made of Knife River Flint (KRF).  Artifacts made of this northern High Plains material are highly sought after because of the aesthetic qualities they exhibit. The following article is a brief description of the attributes of KRF.

The generally accepted source of Knife River Flint is in Dunn and Mercer Counties in western North Dakota. KRF is an exceptionally high-quality and durable toolstone. It has a wide distribution range throughout the states and provinces adjacent to and even farther removed from its source in North Dakota. It is distinctive in appearance, and identification based on general appearance is usually considered unequivocal (Frison 1982).

KRF is a finely textured, uniform, nonporous, brown to dark brown, translucent chert (flint). It occurs in secondary deposits in the form of subangular, tabular, and blocky pieces that can range in size from gravel to small boulders.

The presence of  white fossil plant fragments in the brown translucent flint help distinguish it from other look-alike materials such as Scenic chalcedony and others sources from the White River group silicates found in western South Dakota and northwestern Nebraska.  Ultraviolet (UV) fluorescence can be useful in distinguishing KRF from the similar look-alike materials.

Patination of KRF artifacts can vary from absent  to a very intense cream-white patina. Patination is caused by dissolution of silica from the surface of the artifact and the patina is almost always the most intense on the upper facing surface of a buried artifact. Variables important to the amount of patination include time, pH, moisture, and temperature and will vary greatly from one region to another. However, lack of patination is not an indicator of age as unpatinated artifacts may date from the Paleoindian through Late Prehistoric periods (Root et al. 1986).  The majority of the KRF artifacts that I have seen or found from south central Nebraska have a near absence of white patina  but oftentimes exhibit a very light lustrous haze or a light bluish surface haze. 

Because KRF is such a high quality lithic it is not unusual to find artifacts made from it at great distances from its source. This is especially true of artifacts made by Paleoindian cultures. These early cultures were very mobile and long distance transport of high quality lithics was not an uncommon practice. A number of Paleoindian artifacts made of KRF have been found in southern Nebraska at an approximate distance of 500 miles from the lithic source.