Long before humans carved tools or painted cave walls, our ancestors were already collecting something notably less practical: crystals. Smooth, geometric, and often transparent, these natural objects hold no obvious survival value. Yet, they were carried, kept, and seemingly cherished.
Now, a new empirical study offers a striking clue as to why.
Drawing on a series of controlled experiments with our closest living relatives, chimpanzees, researchers have uncovered evidence that the fascination with crystals may be strongly rooted in the primate brain’s evolutionary wiring.
The findings suggest that what captivated early humans hundreds of thousands of years ago may not be uniquely human at all.
“The experiments aimed to identify which physical properties of crystals might have attracted chimpanzees and hominins,” researchers write. “Our results suggest that enculturated chimpanzees can identify and distinguish crystals from other types of stones. We found that transparency and geometric shape were the two attractors guiding chimpanzees.”
A Mystery That Dates Back Nearly 800,000 Years
Archaeological evidence shows that crystals, particularly quartz and calcite, appear at early human sites dating back 780,000 years. These objects show no signs of having been used as tools, weapons, or ornaments. They weren’t modified or shaped. And yet, they were deliberately transported from their natural locations to human shelters.
That behavior raises the fundamental question: Why would early humans collect something with no apparent function?
To explore this, a team of Spanish researchers turned to chimpanzees. If modern apes show similar preferences, it could point to a shared cognitive predisposition—one that predates modern humans and even Homo sapiens.
Putting Crystal “Allure” to the Test
Researchers designed a series of experiments involving two groups of enculturated chimpanzees living in a semi-natural sanctuary environment. The goal was to determine whether the animals would show a preference for crystals over ordinary stones, and if so, why.
In one experiment, dubbed “The Monolith,” chimpanzees were presented with a transparent quartz crystal and a similarly sized rock. Both were mounted on identical platforms.
The results showed that while both objects initially drew attention, the chimpanzees overwhelmingly preferred the crystal. They spent significantly more time interacting with it, eventually removing it from its pedestal and carrying it into their living spaces, where they continued to examine it for up to two days.
The rock, by contrast, was quickly abandoned.
Even more telling, the chimpanzees appeared to treat the crystal as valuable. Caretakers later had to exchange favored foods, such as bananas and yogurt, to retrieve them, suggesting that the animals perceived them as having an intrinsic value.
A Closer Look: What Makes Crystals So Compelling?
To dig deeper, the researchers conducted additional experiments in which chimpanzees were presented with piles of mixed stones and crystals. The animals consistently selected the crystals, often within seconds, leaving behind ordinary pebbles.
In some cases, chimpanzees carefully inspected the crystals, holding them close to their eyes, rotating them, and even positioning them against the light. One chimp examined a crystal for over 15 minutes, repeatedly studying its transparency and internal structure.
These behaviors suggest more than casual curiosity. Instead, they point to a focused and deliberate interest in specific physical properties.
According to the study, two features stood out as key attractors: transparency and geometric shape.
Crystals are among the few natural objects that combine both. Unlike the irregular, curved forms that dominate the natural world—trees, rocks, landscapes—crystals exhibit straight edges, flat faces, and precise angles. They are, in a sense, nature’s rare examples of Euclidean geometry. This makes them visually distinctive.
At the same time, transparency introduces another layer of intrigue. In nature, transparency is most commonly associated with water. A solid object that shares this property, like a quartz crystal, may create a perceptual paradox, blending familiarity with novelty.
A Shared Cognitive Bias?
If both humans and chimpanzees are drawn to the same properties, symmetry, geometry, and transparency, it suggests that this attraction may stem from a shared evolutionary foundation. In other words, the “crystal allure” may not be cultural or symbolic in origin, but deeply embedded in the cognitive architecture of primates.
The researchers propose that this attraction could have played a subtle but meaningful role in human evolution.
Crystals, with their regular patterns and sharp geometry, may have helped early humans recognize symmetry and structure, skills that later became essential for tool-making, art, and even abstract thinking.
Indeed, the timeline is suggestive. The earliest symmetrical stone tools appear around 1.4 million years ago, with significant improvements emerging roughly 500,000 years ago—around the same period when crystal collection became more common in the archaeological record.
More Than Just Curiosity
The study also challenges long-held assumptions about the origins of symbolic behavior.
For decades, archaeologists have debated when humans began engaging in activities beyond survival—collecting objects for aesthetic, symbolic, or ritual purposes. Crystals may represent one of the earliest examples of such behavior.
And now, the evidence suggests that the roots of that behavior may run deeper than previously thought. Rather than being uniquely human, the impulse to seek out visually striking, unusual objects may be part of a broader cognitive toolkit shared across species.
What Comes Next
Despite its intriguing findings, the study has limitations. The chimpanzees involved were enculturated—meaning they had prior exposure to human-made objects, including those with straight lines and transparent surfaces. This raises the possibility that their preferences may have been influenced by experience.
Future research will need to test wild chimpanzees and other great apes, such as bonobos and gorillas, to determine whether the same attraction holds in more natural settings.
Still, the results offer an intriguing glimpse into why early humans picked up crystals and kept them. The answer, it seems, may lie not in culture or symbolism alone, but in something far older. A shared cognitive spark, ignited by the rare beauty of geometry and light.
“Crystals may have contributed to the development of metaphysical and symbolic thinking, acting as catalysts for the conceptualization of a ‘big beyond,’” researchers write. “Their rarity, optical allure, and geometrical singularity could have imbued them with special meaning, serving as physical representations of ideas beyond the immediate and tangible world.”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com