Have you ever ever discovered your self in a museum’s gallery of human origins, watching a glass case filled with rocks labeled “stone tools,” muttering beneath your breath, “How do they know it’s not just any old rock?”
At first look, it may appear inconceivable to decipher. However as an experimental archaeologist with over a decade of expertise learning and manufacturing stone instruments, I can say that there are telltale indicators {that a} rock has been modified by people or our very historic ancestors, hominins.
This course of, often called flintknapping, could be boiled all the way down to mastering power, angles and rock construction. When carried out correctly, flintknapping creates the recognizable options that archaeologists use to determine stone instruments.
An illustration of conventional flintknapping methods.
Why do stone instruments matter?
John Murray demonstrates his flintknapping abilities for the Glendale Group Faculty Anthropology Membership.
John Okay. Murray
Stone instruments are rocks which were chosen to be used or deliberately altered. This expertise appeared round 3.3 million years in the past and have become important to hominins – all of the dwelling and extinct species that belong to the human lineage. At the moment, we Homo sapiens are the one dwelling hominin.
We aren’t the one dwelling species to make and use stone instruments, although – many different primates do – however the extent to which hominins modify them is unparalleled within the animal kingdom. Monkeys and different apes might maintain a big stone of their arms to crack a nut on a flat, tablelike stone.
However most hominins don’t depend on stones collected as-is. They modify and form them into helpful instruments for quite a lot of duties, together with slicing meat or crops, woodworking, scraping conceal and whilst projectiles.
Stone instruments are necessary to archaeologists as a result of they’re sturdy and protect nicely. This makes them a number of the finest proof for hominin habits and permits us to higher perceive how completely different populations tailored to native environments throughout time and huge geographic areas.
How are stone instruments made?
Hominins manufacture stone instruments by fracturing or abrading rock. Right here, I’m going to concentrate on fractured or flaked stone expertise as a result of instruments made by this method dominate the archaeological report.
The method of flaking includes making use of power to the sting of a stone, often called the placing platform, by percussion or strain to take away parts of the rock, that are known as flakes. With some steerage from a instructor and loads of observe, flintknappers can discover ways to determine a promising platform on a bit of stone, known as a core, and persistently take away flakes from it. When struck, the platform is faraway from the core and is a key function of the flake.
Flakes supply an instantaneous sharp innovative. A flintknapper may also additional modify them into extra particular shapes for different makes use of. An iconic instance of that is the hand ax, which is a core that’s been flaked right into a teardrop form.
Cores, left, are the thing being struck by the flintknapper, and flakes, proper, are the sharp-edged materials faraway from the core. Some cores, like this one from the archaeological web site Pinnacle Level 5-6 in South Africa, could be as small because the tip of a finger.
John Okay. Murray
We frequently use hammerstones or giant items of antler, known as billets, to strike the core’s edge. Repetitive flaking not solely permits a flintknapper to provide a big quantity of sharp innovative within the type of flakes, however provides them the flexibility to form the core to their desired kind … typically with the danger of private harm alongside the way in which. My fingers can attest to this!
A contemporary flintknapper’s toolkit consists of leather-based pads, gloves, security glasses, antler billets (left), onerous hammerstones (proper), and abraders (center-right with grooves), used to rub the sting of the stone to strengthen the platform earlier than placing.
John Okay. Murray
Nevertheless, not each kind of rock has the traits wanted to be flaked right into a instrument. You need the stone to exhibit what’s known as conchoidal fracture. In case you’ve ever seen glass break, you’ve witnessed conchoidal fracture. This easy break, with concentric wavelike ripples, is outlined by the physics of how power strikes by completely different supplies.
Obsidian hand ax made by John Murray, showcasing examples of conchoidal fracture produced whereas making flakes to form it.
John Okay. Murray
When an skilled knapper is making ready to take away a flake, we perceive how the fabric we’re working will break once we strike it, so we are able to predict the form and measurement of the instruments that we’re producing. A stone like obsidian, which is volcanic glass, is the poster baby for conchoidal fracture.
In fact, there may be numerous variation within the high quality of rock that hominins have used for manufacturing stone instruments, and plenty of have made use of lesser high quality stone. Even a number of the earliest toolmakers have been preferentially choosing rocks for sure properties, equivalent to sturdiness.
How are you going to acknowledge stone instruments?
Chances are you’ll hear folks saying that rocks that they discovered of their backyard have been instruments as a result of they “fit perfectly in the hand” or are “tool shaped.” But it surely’s not fairly that simple. Though form and performance might play a job within the last product of a stone instrument, it’s not the smoking gun.
Archaeologists can decide whether or not a bit of rock is a stone instrument primarily based on clues left behind from the method of conchoidal fracture throughout flintknapping.
One such clue is the presence of flake scars, or what we name detrimental removals, which could be discovered on each cores and flakes. These have attribute ridges on a number of sides of the rock that define earlier flake removals – therefore using the time period scar.
Once we see a number of flake scars which are constant of their orientation and measurement versus being random, it’s doubtless the stone in query was intentionally labored on by a hominin.
The second function is what we name the bulb of percussion. It is a bulge within the flake, just under the placing platform, that outcomes from the focus of power when the knapper struck it.
Contemplating that producing a bulb of percussion requires the rock to be struck on a platform at a selected angle with sufficient power to detach it from the stone, it’s inconceivable that this function can be created by pure processes – however not inconceivable. Scientists have discovered naturally produced sharp stone fragments, or naturaliths, all around the world, even in Antarctica.
Nevertheless, when numerous flakes with these diagnostic traits are discovered collectively, it’s unlikely they have been created naturally.
A hand ax made by John Murray exhibits many flake scars, a few of that are outlined in black. The interior floor of three flakes exhibits the bulb of percussion just under the platform.
John Okay. Murray
The ultimate factor to think about when figuring out whether or not a rock is a stone instrument is the context during which it was discovered. Are there many stones within the space that exhibit the traits that we search for when making an attempt to determine a stone instrument? Is the stone instrument fabricated from an unique materials, or is it like the remainder of the rocks close to it?
In case you discover numerous stone instruments in the identical space made out of one kind of rock, you might need stumbled throughout an historic flintknapping workshop. Nevertheless, in case you uncover a instrument that was made out of a kind of stone that may solely be discovered a whole lot of miles away, perhaps somebody traded for this materials or carried it with them.
Attempt it for your self
I believe the easiest way for you to have the ability to be taught to acknowledge whether or not a bit of stone was a instrument or only a rock is to attempt flintknapping your self. I’ve taught greater than 100 folks of all ages to fabricate stone instruments, and most agree: It’s more durable than you’d suppose.
This expertise places you into the minds of our hominin ancestors, making an attempt to deal with one of many earliest issues our lineage confronted: getting a pointy edge from a chunky piece of rock.
