Color:  Yeso Formation Chert ranges from gray to a grayish brown or brown.  However, most chert listed as Yeso ranges from shades of red to a mottled white or light gray and pink (pictured).  The Yeso Formation does produce a white to light gray and pink siltstone and a red to light pink fine grain sandstone, but geological sources does not include chert in these layers of the formation.  Yeso Chert might not be associated with the Yeso Formation or other formations occurring on Mesa del Yeso.

Texture:

Luster:

Silica Fabrics / Fossils:

Patina:

Heat Treatment: 

Knapping: 
 

 

 

 

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distribution Comments:

Yeso Chert occurs around Mesa del Yeso, Soccoro County New Mexico.  However, if this is associated with the Yeso Formation, additional outcroppings could occur in the Lucero Uplift of Valencia, Socorro, and Bernalillo counties, in the La Joya area, Los Pinos Mountains, and in the northern Chupadera Mesa, New Mexico.  Montoya Formation Chert occurs in south central New Mexico and is various shades of pink.  This might be associated with the Montoya Formation.