Chert is sedimentary rock composed of microcrystals of silicon dioxide (SiO2) that grows within the soft sediments that will become limestone or chalk. In these sediments, enormous numbers of silicon dioxide microcrystals grow into irregularly-shaped nodules or concretions as dissolved silica is transported to the formation site by the movement of ground water. If the nodules or concretions are numerous they can enlarge and merge with one another to form a nearly continuous layer of chert within the sediment mass. Because it is highly resistant to weathering, chert is the chief constituent along many natural stream gravels. The loose rock fragments blanket the hillsides in many parts of the state.
Chert is a rock of many names and disguises. The colors of chert may range from buff, green, gray or blue to red, pink, yellow, brown or black. A banded mixture of several colors also is very common. Few people other than geologists actually call it chert. Other Names are applied to the stone depending on its color. Red, brown, reddish-brown and yellowish-brown varieties are called jasper. Black and dark gray specimens are known as flint. Mottled and pink types are called Mozarkite, while some banded varieties have found a home in the agate family.
Chert has a granular microcrystalline form of quartz that is harder than glass, brittle, and breaks with a smooth, rounded or clam-like (conchoidal) fracture with sharp edges when chipped. Chert is a good material for making arrowheads, as well as other scraping and cutting tools. For Native Americans, it was the stone’s hardness and the way it broke that made it invaluable.
Because chert is a very hard material that produces a spark when it is struck against steel, 17th-century-era long-barreled muskets used varieties of natural flint for their strikers.
There are many museums with artifacts displayed that chronicles man’s dependence on industrial minerals. Industrial minerals are the nonmetallic, mined commodities that promote development and sustainment of civilization.
Modern Day Uses
Gravel operations often excavate chert from streams and crush it for use as an aggregate in road construction.
Chert has been used in late nineteenth-century and early twentieth-century headstones or grave markers in Tennessee and other regions.
Modernday Americans who make flaked stone tools like arrowheads and spear points are known as flint knappers.
On To The Cache
Rounded nodules of chert are often referred to as cannonball chert. Cannonball chert forms inside of soft sedimentary limestone rocks which later weather away. Since chert is a much harder material then limestone it resists erosion better. You will be able to see as the nodules will stand out of the limestone. Eventualy the limestone will wear away leaving the chert nodule to fall to the ground.
Near by is an example of these Chert Nodules. to claim a find you need to:
1. Describe the color of chert that is present.
2. Estamate the size of the largest Chert Nodule that you see.
3. Estamate the number of Nodules that you see
4. Take a picture near to the wall with your GPSr or phone in the picture.(OPTIONAL)
5. Email your answers to the email in the profile.
I hope you enjoy this cache