Hornstone

Hornstone, aka Indiana Hornstone, aka Kentucky Blue, aka Wyandotte Cave flint. Found in Wyandotte, Harrison and Crawford counties in Indiana, with other sources near Louisville, Ky. It is found as nodules weathered from the areas limestone. It's color is typically gray to gray-blue color, with a glossy waxy texture. "Bullseyes" are often in the material, being a darker concentric ring, due to the nodular properties of the flint. There may be minute pin holes in the material, resembling the holes in Kentucky Sanora flint. This material was used by all periods of Prehistoric Native Americans.

 References

 Converse Robert N . Ohio Flint Types , Published by The Ohio Archaeological  Society of Ohio 1994  pp 186.