Researchers have discovered a potential explanation for why early humans collected crystals, a behavior observed as far back as 780,000 years ago. A novel study, published in Frontiers in Psychology, suggests that chimpanzees, our closest genetic relatives, exhibit a similar fascination with crystals, indicating a deep-rooted, evolutionary basis for the attraction.
For decades, archaeologists have puzzled over the presence of crystals found at numerous prehistoric sites alongside Homo remains. These stones show no evidence of having been used as tools, weapons, or ornamentation, leaving scientists to question their purpose. The new research, led by Professor Juan Manuel García-Ruiz of the Donostia International Physics Center in San Sebastián, Spain, offers a compelling hypothesis: the aesthetic qualities of crystals themselves may have been the draw.
The study involved two groups of chimpanzees from the Rainfer Foundation, an organization specializing in great ape welfare. Researchers presented the chimpanzees with a large crystal – described as a “monolith” – alongside a similarly sized, ordinary rock. Initially, both objects garnered attention, but the chimps quickly demonstrated a clear preference for the crystal, inspecting it from various angles and, in one instance, carrying it to their sleeping quarters. Researchers were able to retrieve the crystal only by trading it for bananas and yogurt, demonstrating its perceived value.
A second experiment involved smaller quartz crystals mixed with rounded pebbles. The chimpanzees were able to quickly and accurately identify and select the crystals from the pile, even when other types of crystals – pyrite and calcite – with differing shapes were introduced. The chimps repeatedly examined the crystals, holding them up to their eyes to observe their transparency. One chimpanzee, named Sandy, meticulously separated the different crystal types from the pebbles, even using her mouth to transport them, a behavior the researchers noted as unusual and suggestive of valuing the objects.
“She separated the three crystal types, which themselves differed in transparency, symmetry, and luster, from all the pebbles,” said García-Ruiz. “This ability to recognize crystals despite their differences amazed us.”
The researchers concluded that both the transparency and shape of crystals likely contributed to the chimpanzees’ fascination. Crystals, being the only naturally occurring polyhedral solids – meaning they have many flat surfaces – stand out in a natural world dominated by curves and irregular forms. This novelty may have been particularly appealing to early humans attempting to understand their surroundings.
The Atapuerca region of Spain, specifically the Sima de los Huesos site, has yielded significant evidence of early hominin activity, including the remains of pre-Neanderthals dating back approximately 430,000 years. The Sima del Elefante site within Atapuerca contains even earlier evidence of human presence in Western Europe, with fragments of jawbone and teeth dating back 1.1 to 1.2 million years, according to Britannica. The Gran Dolina site, also at Atapuerca, has yielded human remains and tools dating to around 800,000 years ago. These sites provide the archaeological context for the ongoing investigation into hominin behavior.
“Our work helps explain our fascination with crystals and contributes to the understanding of the evolutionary roots of aesthetics and worldview,” García-Ruiz stated. “We now know that we’ve had crystals in our minds for at least six million years.”
