Silicon, the Stone Age, and the Periodic Table of Death and Mystery

“Evolutionary mismatch” is a concept developed in the field of evolutionary psychology. The concept postulates that human brains are wired for conditions that no longer exist. That “we have stone-age brains in modern environments,” and our primitive brains still drive our behaviors (1, 2).

But what does it mean to have a “Stone Age” brain? You’ve probably heard the term Stone Age before, especially if you ever watched the Flintstones (3). It’s a dated term that applies to a period ~2.5 million to 5000 years ago, when humans made and used stone tools. It’s also when our brain size, structure, and neurological connections became, well, “human” (4). Most evolutionary biologists don’t believe that there’s been enough time since the Stone Age for our genetics to have significantly changed, which has interesting health and social-relationship implications effect. We are essentially small-community-hunter-gatherers living in a crowded sedentary world with abundant food (which makes us stressed and fat. Super.)

What these evolutionary psychologists don’t understand is that humans—after surviving the Stone Age, the Bronze Age, the Copper Age, the Iron Age, the Renaissance, the Industrial Age, the Atomic Age (5), and whatever else Age you can think of—are back in the Stone Age. The modern Stone Age.

We now live in the Digital or Information Age, also called the Silicon age, all because of the periodic table element Silicon (Si). Why? Silicon is a critical material in the semiconductor and high-technology industries of supercomputers, cellphones, and microchips. Si is also a critical material for stones. Isn’t that amazing? The Stone Age brains that once drove us to knap obsidian (high in silicon dioxide—SiO₂) into wickedly sharp knives, spear points, and arrowheads are the same brains that make silicon semiconductors for gaming consoles (6) so we can play Pac-Man, Tetris, and Grand Theft Auto 8 (7).

Silicon is a member of group 14 in the periodic table with the atomic number 14. Directly above it is carbon (C), atomic number 6. All of Earth’s life-forms are carbon-based because carbon’s atomic structure is versatile. It can interact with four other atoms, create relatively stable molecules, which allow the biochemical construction of life polymers (like proteins, fats, and nucleic acids). Hypothetical biochemistry (yes, there is such a thing) postulates that silicon-based life forms could exist (8) because Si chemistry is similar to carbon’s. It can also bond with four other atoms and combine to create polymers. Who knew? Welp, Star Trek, the Original Series (1966-1969) did. “Devil in the Dark”, Season 1, Episode 25 (9) dealt with the Horta, a rock or Silicon-based life-form. It was the first time McCoy ever used, “I’m a Doctor, Jim, not a …” in this case, bricklayer (10). You know, because of the live rock.

This article/episode could end here because the Horta caused the deaths of human miners on its planet and the miners caused the deaths of Hortas, all of which fulfill the promise of the Periodic Table of DEATH and Mystery. But what about the promise of green obsidian? That’s where the MYSTERY comes in and takes us back to a first Stone Age—sort of.

And back to obsidian. Its brittleness and ability to fracture into sharp-edged shards made obsidian highly prized. (It’s even used in scalpels you can buy online! (11)) In the past, obsidian was traded by communities and civilizations who controlled the obsidian mines to communities and civilizations who didn’t. One such civilization was the Teotihuacán in central America.

Archeologists believe the Teotihuacán first appeared around 400 B.C. and built to a population of ~200,000 thousand people before it collapsed in 400 A.D. We know very little about the language, religion, and culture. Even their name was bestowed on them by the Aztecs. Teotihuacán means “the place where the gods were created” (12) in Nahuatl. But we do know they controlled the only green obsidian mines in the region.

Green obsidian—a stone as transparent as glass with elemental impurities that create its rare color (13)—was considered a luxury trade good. Archaeologists have found it hundreds to thousands of miles away from its origin: in a ritual cremation in Belize (16), blades discovered in Mayan temples (14), and a broken green obsidian knife found by chance in the Panhandle of Texas in the 1930s or 40s by a rancher’s teenage son, Lloyd Erwin (15). Chores on his family’s ranch meant long rides over vast plains where he’d pick up artifacts and arrowheads, arrange his finds in fancy patterns, and place them in shadow boxes to hang on ranch house walls.

After Mr. Lloyd’s passing, his daughter-in-law, Charlene Erwin, approached Matthew Boulanger, an anthologist from Southern Methodist University, to authenticate some of the obsidian pieces. Boulanger believes the knife traveled to the panhandle region with the Spanish explorer Francisco Vasquez de Coronado when he and his expedition (including ~2000 “indios amigos”) trekked across the Southwest in search of fabled cities of gold (17). Boulanger even published a paper about it: Boulanger, Matthew. (2024). Central Mexican origin for an obsidian prismatic blade from the Texas Panhandle. 2. 1-11. And as part of that paper, he did a comparative analysis of the Erwin blade and green obsidian from Pachuca, Hidalgo, Mexico. Lo-and-behold, Boulanger found the broken obsidian knife to have the same chemical composition as green obsidian from the famous Teotihuacán mines. So Green Obsidian = Coronado’s journey across the Southwest 470 years ago. Amazing.

A quick note: Coronado never found the cities of gold (Au, atomic number 79), but maybe his journey will be told in a future Periodic Table of Death and Mystery (18).