Chert nodule ("Indiana hornstone") (probably Mississippian; Indiana, USA) 7
Chert from the Mississippian of Indiana, USA. (~9.0 centimeters across at its widest)
This rock is "Indiana hornstone". If correctly attributed, it is a chert nodule derived from a Mississippian-aged limestone unit in southern Indiana - likely Harrison County or Crawford County.
Chert is a cryptocrystalline, quartzose sedimentary rock. It consists of tiny quartz crystals too small to see with normal microscopes ("crypto" means "hidden").
In this sample, the dark-colored material is unaltered chert (referred to by some as "flint"). The light-colored material is a weathering rind, which is called "cortex" by flintknappers.
Early American Indians used Indiana hornstone to make arrowheads, spearpoints, and other stone tools.
Locality: unrecorded/undisclosed site in Indiana (possibly southern Indiana), USA
Chert nodule ("Indiana hornstone") (probably Mississippian; Indiana, USA) 7
Chert from the Mississippian of Indiana, USA. (~9.0 centimeters across at its widest)
This rock is "Indiana hornstone". If correctly attributed, it is a chert nodule derived from a Mississippian-aged limestone unit in southern Indiana - likely Harrison County or Crawford County.
Chert is a cryptocrystalline, quartzose sedimentary rock. It consists of tiny quartz crystals too small to see with normal microscopes ("crypto" means "hidden").
In this sample, the dark-colored material is unaltered chert (referred to by some as "flint"). The light-colored material is a weathering rind, which is called "cortex" by flintknappers.
Early American Indians used Indiana hornstone to make arrowheads, spearpoints, and other stone tools.
Locality: unrecorded/undisclosed site in Indiana (possibly southern Indiana), USA