Updated: May 9, 2022
Fossil hunting was my route into Bushcraft. Along with a passion for sorting through beaches worth of stones for sharks teeth and other relics, I was desperate to find an arrowhead, or a hand axe or.. something. And until this last week or two, I had never found a thing. Just the left behind debitage from where some long dead human has sat and knapped. Its a popular hobby but one that can be very frustrating. Some areas of the country are literally covered with flint. almost every rock you see in a ploughed field is broken flint and after a while they all start to look like tools... so how do you tell the difference between tools ( or even just waste flakes/ debitage) and rocks shattered by eons of frosts, glacial activity and now farming!? One of the best ways is to have a go at knapping yourself, get to understand how flint works, how it breaks. what it looks like when i goes right.. and what it looks like when it goes wrong. Bulb of percussion and striking platform When flint is struck, the shockwave spreads out in a cone. When we look at a flake surface, we will see one half of that cone. At the start it is tight, around 70 degrees, but as the shockwave looses energy it flattens. This meas that near the site of the 'strike' there will be a bulge- the bulb of percussion, often marked by ripples spreading out from the point of impact like ripples on a puddle. This can occur naturally, ( think of rocks clinking together in the sea or under the plough), but it indicates a single point of impact. To detach a flake that can become a tool, or a flake that can shape a nice thin tool, the right angle is very important, this is seldom achieved in nature. There my be edge damage from a piece trolling about in a stream or glacier, but the flakes will likely be short, disorganised, random and often ending in a step rather than tapering out to nothing. ( this happens with knapping too, and is very annoying! Often you can see where someone has attempted to remove a step or 'hinge' and eventally given up.) Percussion from a hammerstone ( or another accidental stone clink) leaves a circular, or semicircular 'bruise' in flint, usually quite small (
2-3mm accross_. This is the top of that cone shaped crack caused by the shockwave. You may see 'miss hits' near the striking platform where a flake has been successfully removed ( a sign of the lack of skill of the knapper!). To remove a flake, in most cases, you strike near an edge , if you are seeing percussion scars in the middle of a piece, it may be due to low skill, or may be due to natural/accidental factors. Struck flake on the left showing bulb of percussion and strike point/ striking platform, natural damage on the right- also note the different patina.
Patina Patina is the weathering process that alters the outside of the flint over time. It used to be thought of as a way to age flint accurately. But we now know it doesn't progress at the same rate- if the flint was well buried, it may have no visible patina at all, even if it was knapped tens of thousands of years ago, while more recent flakes in a sandy/ acidic soil may have a thick patina after only a few thousand years. However, it can give you a clue, especially if you have a lot of material in the same site and can compare It can help you distinguish between old knapping and new damage. If the 'retouch' ( small flakes used to shape an edge) is newer than the patina on the larger surfaces..... the 'retouch' may be edge damage, not knapping. It can give you an indication of what colour the historic flints may be and help you to pick them out of the crowd- but will vary from area to area, and is only a rough guide. Patina can vary, from a slight sand polished 'waxiness' to the surface, to a milky discoloration to a complete colour chance that extends to a few millimetres. Black Norfolk flint, can weather completely chalk white after even 5-6,000 years as the piles of debitage at Grimes Graves show. This flake shows a milky surface patina consistent with the other finds from that area ( neolithic) and some much later edge damage on the bottom right.
Frost damage Frost damage is a nightmare for knappers. Flint is surprisingly porous. Over millennia , thousands of winters and more than a couple of ice ages, water ice and time can wreak havok on good stone. Water gets into cracks ( natural percussion scars, inclusions, fossils etc) Freezes, expands, and forces off a flake. these can bear an uncanny resemblance to manmade flake scars.
These are both 'geofacts' not human made
Angles and organisation Often ( especially if you have tried your hand at knapping) it is possible to see the flint through the eyes of the person who knapped it. The problems they faced, inclusions in the stone, the odd bump on the back that collected hinge fractures and refused to be removed ( grrr). Recognising the thought, the plan behind the scars on a piece of stone can help you determine whether it was natural, manmade, or a waste flake. If there is an edge, is it a usable edge ( if it isn't usable now, can the patina tell you what is more recent damage?) Scrapers are an oft mis identified item. Most scrapers are only flaked on one side to leave a flat face with a strong and only-microscopically-serrated edge- because that's what works! If you understand how the tools were used, a lot of the nonsense falls away- if it didn't work that well, they wouldn't have bothered to use it- they weren't stupid! If its worked on both sides to form a straightish edge with minimal zig zag, think in terms of cutting edges.
Of course there were good knappers, and less good ones. Some tools were made to be kept reused and treasured, some were single use then discarded. Sometimes it can be quite ambiguous.
A good example of this is Neolithic cores- they look like they've been bashed from every direction... and yet there will be very few 'miss hits' evident, and all the flaking will be the same age, the same patina. They were just a way of producing flakes that could be turned into other tools, while leaving opportunities ( ridges and striking platforms to produce more. Another mistake people make is to look at the shape of the flint from one direction, and see a 'triangular' shape which screams hand axe, yet it has no edge. These were tools or cores for creating them- they have to function; and axe without an edge, is not an axe. its a ruined rock! You only have to look at eBay to find dozens of people who have made that mistake. Willful deceit? or wishful thinking.. I'm not sure. but there are certainly a lot of people trying to sell frost shattered and plough damaged flint as authentic tools. Happy hunting!