Man has been working rocks, stone, and bone into tools, utensils, and weapons for millions of years. Given its abundance in nature, rocks and bone are perfect materials for making tools and weapons in an emergency wilderness survival situation.
How are tools and weapons constructed from rocks?
All stone-working methods require “lithic reduction” and involve the use of a hard hammer (i.e. a hammerstone) and a soft hammer fabricator (wood, bone, or antler), to detach “lithic flakes” from a lump of tool stone (called a lithic core). Given the appropriate stone materials, a stone worker learns to control and direct the application of force so as to shape the material being worked on.
As flakes are detached in sequence, the original mass of stone is gradually reduced. Lithic reduction techniques may be performed in order to obtain sharp flakes, which can be used for a variety of tools such as arrowheads (given the properties of rock, the flakes created can be very sharp, often with edges only a few molecules thick), or to rough out a blank for additional refinement.
To begin, determine the characteristics of the rock itself. Ask yourself these questions:
- Does it crumble easily?
- Can it be ground?
- Does it split like slate?
- Can a flake be struck off with a glancing blow and if so, does it create a mussel-shaped fracture?
The answer to these questions will dictate which type of stone or bone-working technique you use to make the tool or weapon.
Articles commonly made from rock or bone
- Stone working tools
- Arrow heads
- Spear points
- Axe heads
- Fish hooks
- Sewing needles
- Awls and drill bits
- Spoons and ladles
Types of rock/stone
When working stone, rock with fissures that produce straight line fractures are more difficult to work and thus, less desirable for stone working. Instead, look for fine-grained stones that lack natural “planes of separation” (which would cause them to split along pre-defined lines). Fine-grained rocks produce desirable stone-working fractures called “conchoidal fractures” (a curved breakage that resembles the concentric ripples of a mussel shell). Examples of the types of rock that make excellent raw materials for stone working tools include the following:
Chert is a fine-grained rock that may contain small fossils. It varies in color but is usually white to black. There are numerous varieties of chert including flint, jasper, chalcedony, agate, onyx, opal, and porcelanite.
Flint is a hard, sedimentary rock that occurs chiefly as nodules in other sedimentary rocks such as chalks and limestones. The inside of flint (it typically has a thin, chalk-like layer on the outside) is usually dark gray, black, green, white, or brown and often has a waxy or glassy appearance. When flint is struck against steel, the flint edge will produce sparks (technically, it shaves off a tiny particle of steel which exposes iron which reacts with oxygen in the air to ignite with a spark).
Most flint is found naturally covered in a layer of white chalk-like material (cortex). The first stage of flint working is to remove the cortex in order to expose the gray or black flint.
Obsidian is a type of volcanic glass that is commonly found within ancient lava flows. It is hard and brittle and fractures with very sharp edges. It is usually dark in color but in some cases, the inclusion of small clusters of cristobalite will give it a blotchy or snowflake pattern. Obsidian may contain gas bubbles remaining from the lava flow. In the United States, it is commonly found in the states of Arizona, Colorado, New Mexico, Texas, Utah, Washington, Oregon, Idaho, Virginia, Pennsylvania, and North Carolina.
Jaspar has a glassy look like obsidian, but is not as translucent-looking. It is typically red, yellow, brown, or green in color but given modification by diffusion of materials, may be mottled with any color.
Chalcedony is a form of silica composed of very fine twines of quartz and moganite. It has a waxy luster and may be semitransparent or translucent. It can assume a wide range of colors but is most often white to gray, grayish blue, reddish-brown, or brown. It comes in many varieties, most notably agate, moss agate, and onyx.
Ryholite is a type of volcanic rock. It may have any texture from glassy to rough and often appears similar to granite. Rhyolites that have cooled quickly form obsidian and thus, both may be found alongside each other.
Felsite (or felstone) is a type of volcanic rock. It is generally white or light gray but may be red or tan in color. It is typically formed by the tight compaction of fine volcanic ash and may be found alongside rhyolite or obsidian.
Quartzite is a hard rock that was originally sandstone that converted to quartzite through heat and pressure. It is usually white or gray in color but may be red or various shades of pink. Occasionally mineral impurities may color it yellow, green, blue, or orange. Quartzite has a grainy, sandpaper-like surface which may become glassy in appearance. It is very resistant to weathering and thus, may be found on bare ridges and hilltops.
Types of strikes used to shape stone into tools
There are various methods used to strike the stone in order to remove flakes, each conducted in sequence as the tool begins to take shape. As you work to shape rocks, chips and flakes will be struck off, many of which are razor sharp. Regardless of what you are building, save these flakes for use as arrowheads (using pressure flaking to fine-tune the edge).
Direct percussion (hard-hammer percussion)
As the name implies, direct percussion involves striking the rock with another, harder stone. It is typically the first stage of stone work as it produces larger flakes and a less accurate shape. The blows should be glancing blows (a direct blow will simply shatter the core). The required degree of the blow will vary depending upon the material being struck (obsidians require a very indirect blow while harder materials such as jaspers, cherts, and flints will require a more direct blow but still glancing).
A suitable platform to rest the target rock on could be a knee covered with leather or a tree stump. If the platform is too hard, the hammer may break instead of the rock you are working. The hard-hammer method is believed to have been used to make some of the earliest stone tools ever found, some of which date from over 2 million years ago.
Pecking and crumbling
This technique (a form of direct percussion) is useful for rocks that will not split easily and involves repeated striking the rock to knock off tiny pieces and ultimately shaping the rock to the desired shape. It is what most people envision when thinking about making rock/stone tools. Pecking involves repeatedly hammering the target rock to detach sharp flakes of rock. It can be done to obtain the tiny, sharp flakes or to rough out a blank for later refinement into a projectile point, knife, or other object. Quartzite stone makes an excellent hammer for pecking. This technique can also be used to cut grooves in stones in order to more easily split them into two pieces.
Since they lack natural planes of separation, stone such as chert, flint, obsidian, chalcedony, rhyolite, felsite, and quartzite are excellent source materials for pecking (see Types of Rock above for pictures).
Knapping is the technique (a form of direct percussion) used to work glassy rocks or rocks that break like glass with a mussel-shaped fracture. This is called a “conchoidal” fracture and is common to many rocks. Because the rocks fracture with this common pattern, you can predict how the rock will break when struck. This technique is the most complicated but given the clam-shaped fracture, is useful for axe, arrow heads, or other flat-faced stones.
Begin by finding a suitable stone to work. Obsidian works great but flint or chert can also be used if it has not already developed hairline fractures from weathering (these hairline fractures cause the rock to break with unanticipated fracture lines). To test a flint rock for solidity, tap it with a hammer stone and note if it rings out with a clear, clean note.
Next, select an appropriate “hammer” rock to knap with. These rocks are rounded stones typically made of quartzite that will not shatter when struck against the flint. They should be as heavy as can be managed (about the size of an apple or lemon).
Indirect percussion (soft-hammer percussion)
Indirect percussion or soft-hammer techniques, are more precise than hard hammer methods of shaping stone and produce smaller and thinner flakes than hard hammers do. The method is often used after hard-hammer flaking to do finer work such as removing unwanted knobs or high spots on the blanks.
Indirect percussion requires use of a punch and hammer. A straight piece of antler that has been shaped to have a blunted point makes an excellent punch in the wilderness. The antler punch can then be placed against the rock surface (held with the thumb and forefinger) and struck with a hammer or wooden billet in order to apply large force to a small area of the stone tool.
Since indirect percussion requires one hand hold the hammer and one hold the punch, a third object must be used to hold the targeted piece of stone while it is struck. Of course a clamp or vise would work best but in the wilderness, would require finding some sort of object to wedge the stone tool into (e.g. a stump of wood). If no wedge-like surface can be found, any stable platform on which to place the target rock will suffice.
Pressure flaking involves removing small, narrow flakes along the edge of a stone tool. It is often used to do detailed thinning and shaping of a stone tool and thus, is typically the last step in the stone working process. As the name implies, pressure flaking requires removal of lithic flakes using pressure rather than striking it with a percussor.
A pressure flaker can be constructed from an antler tine and a small pad of buckskin leather. Place the leather pad in your left hand so that it acts as a cushion. Place the rock in the leather pad (you may need to roll the leather to provide a tight grip). Holding the antler tine in your right hand, apply hard pressure to the edge of a flake to remove a tiny flake. This technique is excellent for “sharping” the flakes further. Note that the angle at which you apply the pressure will determine the angle of edge you achieve.
Modern hobbyists may use pressure flaking tools with a copper or brass tip to make the job easier. These metal punches tend to wear down less and are less likely to break under pressure.
Techniques used to shape rock into tools
In addition to the striking methods above, there are several other techniques that can be used to shape the tool.
Abrading and grinding
Even hard rock can be abraded, scuffed, or ground, using an abrasive rock such as sandstone. Abrading is needed to give stone tool polish and sharpness. Abrasive stones of different coarseness are used to vary the smoothness of the polish with the final polish being rendered with bark or animal leather.
Incise engraving and splitting
Incise engraving is the process of cutting or abrading a groove into the rook so that the application of a sharp blow or snapping force will break the rock in a precise manner. The technique works best with hard, dense rocks (that will used for drill bits, chisels, blades, and cutting tools). Incise engraving can be done using a sawing motion with coarse rocks such as hard sandstone or thin slabs of rock such as slate. Water and sand can be added to act as an extra abrasive.
Splitting can often be done without engraving by picking a suitable rock with naturally formed fault lines. A wedge-shaped rock can be placed against the naturally formed lines and struck with another rock to split the rock. If the rock does not split but instead widens the fault line, choose another, larger wedge and repeat the process.
Drilling into rocks can be useful for making fishing sinkers, spindle fly wheels, and attachment points for handles. Even the hardest rock can be drilled, surprisingly, with a wooden drill bit. Simply rotate the drill between the hands by means of a bow or pump drill. Water and sand can be added under the tip of the bit to provide additional abrasiveness.
Nibbling involves use of a “nibbler”, typically an antler tine with a notch ground into the end. This notch can be placed on edges of the target and pried in order to crumble small pieces off the target rock. The method (along with pressure flaking) is often used to notch the stone for lashing to an arrow shaft.
Using bone to make primitive weapons and tools
Once you have a cache of rock tools created, you can create additional tools using bone. Bone is capable of taking a sharp edge while remaining flexible. Bone is an excellent material for projectile points, hook barbs, and sewing needles.
When working with bone (or antlers), try to utilize the bones natural shape in your design. Bone can be somewhat shaped by heating with hot water or steam and then bending into the desired shape. Once cooled, it will retain the bent shape. Bone can be softened by soaking but may also be worked dry.
Smashing is the quick and dirty way to shape bone. Simply smash the bone with a rock or boulder and save the pieces that will be useful for your purposes.
A rock blade shaped with a pressure-flaked (see above) serrated edge can be used to saw a bone.
Similar to sawing, a stone tool can be used to score a deep groove in the bone so that it may be easily splintered.
Useful in concert with scoring, splinters can be split off by driving a chisel-shaped wedge into the bone.
Once the bone has been blanked out (roughly-shaped), a sharp flake or blade can be used to scrape across the bone at a ninety-degree angle to scrape off fine shavings in order to fine-tune the shape of the tool.
Bone should be worked slowly and carefully to avoid unexpected breakage. Abrading is the best way to work down a piece of bone (and to put a sharp edge on bone blades). Using a sandstone block, sand out the shape you are aiming for.
Bone can be drilled or notched using a stone drill. A pilot hole may be punched out (using a small rock) to keep the drill bit from skating over the bone’s hard surface.
Using antler (tines) to make primitive weapons and tools
Although antler tines are much harder than bone, working antler into a weapon or tool is similar to working with bone.
Antler is extremely difficult to cut and thus, burning may be required to weaken the antler. A fire brand (glowing stick from a fire) or embers can be applied to the antler to burn it away. Once the brand is placed against the antler, blow on it to increase the heat and scorch the antler. The scorched portion of the antler will be brittle and can be struck with a stone to break away.
Antler can be sawed with difficulty. A charred or thinned antler may make sawing a viable option.
Incising can be done just as with bone. However, since antler is more flexible than bone, the grooves must be cut deeper.
Abrading and scraping
Both abrading and scraping techniques can be used in the same way as for bone. A sharp rock blade can be used to scrape across the antler at a ninety-degree angle or a sandstone block can be used to sand out the shape you are aiming for.
Soak the antler for a day or two to soften it then carve it using a sharp flake of stone or engraving tool.
Additional materials used to make primitive tools
Teeth, especially sharp incisor teeth, may be used to carve finer details into wood or bone.
Shells can be worked much like slate. Pressure flaking is typically quite effective. Typically, it is worked by simply snapping or crumbling it to a rough shape using a small pointed pebble and a larger anvil stone. Once the rough shape is obtained, abrade the finer details using a coarse abrading stone.
Note that the natural shape of shells makes them excelled for spoons and ladles (haft the shell onto a handle of wood).