The Point of Projectiles: What Exactly is Flintknapping?
By Wolf Whitney-Hul

“I have been flintknapping on and off since 2018 and rarely turn out a good point, but I am improving, and I am always happy to demonstrate to our visitors and answer questions about flintknapping, experiential archaeology, and archaeology in general! Visit my Ask an Archaeologist sessions every other Wednesday from 11am to 1pm, the last this season will be April 23rd and May 7th!” – Wolf Whitney-Hul

Come by the Presidio on a Wednesday and you might hear a distinctive tapping, crunch-crack sound. Follow your ears and you’ll run into Wolf, practicing what archaeologists call flintknapping. It’s the process of taking rocks containing high amounts of silica and breaking them down with wood, bone, stone, and sometimes metal tools until they can be used as an arrow or spear point, a knife, or a scraper for processing hides. In the Presidio’s display cases you will find several projectile points lined up as a sort of timeline, one which is a key for dating sites across the Tucson Basin.

These points were found during excavations at the Presidio and show the changes in points over nearly three thousand years. The smaller Cienega Phase projectile point is made from obsidian.

The first people to live in the Tucson area could have climbed Tumamoc Hill for volcanic rocks or even walked the riverbeds of the Santa Cruz to find river cobbles high in silica. They traded with other indigenous groups for materials like obsidian, which can be found in Northern Arizona, Southern California, and across Western and Northern New Mexico. Obsidian is found all through Tucson’s archaeological record, showing that the people living in our valley have always been connected to the outside world.

Most people think of obsidian as a glassy black stone, but the minerals found in the source volcano can lead to reddish mahogany obsidian, blue-veined spiderweb obsidian, and more! By looking at the minerals present in obsidian found in archaeological sites we can trace it back to a source volcano or even a source eruption.

In Southern Arizona the oldest finds are large, leaflike points several inches long. These projectile points, known as Clovis Points, were used by indigenous people over twelve thousand years ago to tip spears and throwing darts used to hunt mammoths and other large prehistoric animals during the last ice age. While none have been found in the Tucson Basin, several mammoth kill sites are along the San Pedro River to the east of the Santa Cruz at Naco and Murray Springs. Over time we see the points shrink and nearly ten thousand years later the Hohokam make points smaller than a fingernail and spined points nearly two inches long and less than a half inch wide. The style, shape, and size of projectile points can help archaeologists determine the time period in which they may have been made, helping to date sites during excavation.

These replica projectile points made by Allen Denoyer show the difference in size between the dart points used with a spear-throwing tool called an atlatl and those used on arrows.

Flintknapping can be done because silica in the rock makes knappable materials break easily along cone-shaped lines called conchoidal fractures, with a flintknapper taking slim flakes of rock off the source stone, or core. By manipulating the angle of the strike, and the angle of the cone, a flintknapper can flake their stone into many different shapes. There is no one way for an arrowhead to look. Their design varies across time depending on the culture that made them and the type of hunting they were used for.

The basic tools for anyone planning on making stone tools. Antler and stone hammers surrounding finished and in progress points of chert, obsidian, and basalt.

To make a flaked stone tool, you have to find a rock that has a high amount of silica in it. Obsidian and flint are great but can be hard to find! Cherts, agates, jaspers, quartzite, and even basalt might have to be placed in a fire overnight to help crack the hard stone, but all make good tools. After you find your material, you can roughen up the outside of it with a rock to prepare a platform, take a breath, and strike with another rock. After breaking down the material into manageable pieces, or flakes, and discarding the rough outer material, you swap from your stone hammer to something softer. Modern flintknappers like to use shed deer antler, the thick base for a hammer and the thinner tines as a pressure flaker to split smaller flakes off the emerging tool.

Flintknapping is tricky, you must pay constant attention to your rock to be sure you aren’t leaving material that can’t be removed later. This takes practice, experimentation with how rocks break and how to angle that break. Becoming a good flintknapper takes years.