Chert nodule ("Indiana hornstone") (probably Mississippian; Indiana, USA) 7 : 無料・フリー素材/写真
Chert nodule ("Indiana hornstone") (probably Mississippian; Indiana, USA) 7 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | 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 |
| 撮影日 | 2018-10-24 16:12:19 |
| 撮影者 | James St. John |
| タグ | |
| 撮影地 |