While people have often heard about chert and flint, either while hiking or while reading, few people actually know very much about the materials.
In this article, we’ll give you the background on each stone, and explain how they are similar and different.
Chert vs Flint (EXPLAINED)
For about 2.5 million years, humans shaped stones into tools.
In the stone age, early humans relied on their environment to survive, turning microcrystalline quartz into tools, such as shovels, hoes, and axes.
The term microcrystalline quartz refers to three stones commonly known as chert, flint, jasper, and novaculite.
Chert and flint became go to stones for shaping since the properties of these quartz materials made it simple to chip off pieces or break them in half.
As easily as they could break, once shaped, they kept their edge and could prove deadly when used as part of a weapon.
Frequently, these hearty weapons and tools survive, the only reminder of once mighty prehistoric cultures.
Although people tend to intermingle the names of these stones, each refers to a different type of micro crystalline quartz.
Each has its own properties that differentiate from the other and knowing them can help you quickly identify which quartz type you have.
Interestingly, although the names aren’t interchangeable, even among those knowledgeable on the subject of the rocks and their uses, different names get used.
It depends largely on the academic area of study.
While archaeologists and historians use the word flint, geologists favor chert.
If the stone was used for tool-making, it would likely be flint since chert provides poor knapping.
Knapping refers to using a rock or stone to shape another rock or stone for use as a tool, such as sharpening it to make a knife.
What is Chert?
Chert as a geologic formation is a sedimentary rock that can serve as a reservoir for oil and gas.
For example, in West Virginia, a large pocket of natural gas occurs within such as the rock formation, known as the Huntersville Chert.
Chert can take on various colors.
Gray is common, as is white and pink.
It can exhibit a solid color or contain bands of other minerals or fossils.
People can confuse agate and chert because of the colors.
It typically occurs as an opaque stone exhibiting a coarse texture.
Chert can have many fractures or voids in it.
It was commonly used for making scraping tools and arrowheads.
The exception to these colors exists in Australia.
The quartz known as mookaite, found in Western Australia in the Windalia Radiolarite rock formation.
These form in color patterns of maroon, cream, red, and yellow.
The radiolarite cherts formed from shells of the marine animal radiolarians.
They’re found on the ocean floor as well as in seafloor sediments.
These form in different colors than other radiolarites because a portion of the Windalia Radiolarite incurred surface exposure.
Here, the radiolarite became stained by the groundwater and took on a rainbow of colors including white, yellow, cream, brown, red, maroon, and purple.
Once polished and shaped, these vivid and tough rocks make ideal cabochons.
What is Flint?
More commonly used for tool making and weapons, flint occurs in immense rock formations.
Two such formations exist in the US – one in northern Texas called the Alibates Flint and one in eastern Ohio known as Vanport Flint.
When an archaeologist uncovers an artifact, whether a tool or weapon, the stone portion gets referred to as a flint.
Native American nations used these flints for such projects as well as trading the quartz.
Flint can break predictably, thus allowing the toolmaker to create a sharper edge.
This made the flint quartz easier to form into arrowheads, knife blades, and axes.
It exhibits an extremely fine grain size plus a bit of luster. Flint occurs in black, brown or grey, typically translucent.
Red Jasper vs Flint vs Chert
If you see a red stone referred to as flint or chert, your colleague doesn’t know its quartz.
The red stone is red jasper, typically opaque.
In the US, you can find a red jasper in many states, including states in the Pacific NW and in the NE.
Rather than tool making or weapons, the miner would shape this type of quartz to make cabochons, round or oval gems, from it.
After shaping and polishing, the jasper takes on a shiny red and the veins of gray or blue present in it show through.
You can see it commonly used in Native American jewelry, especially necklaces, bracelets, and rings, its red only rivalled by the popularity of the greenish blue of turquoise.
Rather than a weapon, the novaculite provides an ideal sharpening stone.
Found in central Arkansas, in the Ouachita Mountains, these gray stones provide a rough, conchoidal surface that you can easily sharpen another stone using.
Used for sharpening knives, spears, and axes, among other weapons, the novaculite quartz from the Arkansas Novaculite Formation can also sharpen steel blades.
Novaculite sharpening stones were most popular from the early 1800s into the mid-1900s – until synthetic sharpening stones and artificial abrasives began to compete on the basis of price.
Today, many people still make a special effort to obtain a “Washita Stone”, or an “Arkansas Stone” cut from the Arkansas Novaculite Formation.
Their reputation still influences the decisions of many customers.
What do they have in common?
You can find forms of quartz sedimentary rocks.
They appear as round pebbles or as angular or oval sand grains.
When just freed from a rock by hammering or a natural occurrence such as an earthquake, the quartz appears angular.
If you find it after exposure to water, such as in a river bed or in the ocean, the angles give way to a spherical shape.
The work of a rock tumbler has already been done for you.
Both flint and chert contain small quartz crystals and they fracture more like glass than like quartz crystals.
This makes them easy to shape into bladed implements, such as spear heads.
By now, you can take a hike on the weekend to any area with quartz formations and you will be able to tell which type of rock you found.
If you want to, this lets you gather rocks to take home for polishing and either jewelry making or your own attempt to make Stone Age-type implements.
You can find out what it would have been like to farm and hunt with handmade implements.