Crystals have held a special fascination for people since time immemorial. Archaeological findings suggest that our ancestors were collecting the shiny objects 780,000 years ago – without any obvious practical use for them. But why are we so attracted to crystals? And when did this preference arise? Experiments with chimpanzees now show that our closest relatives are also enthusiastic about crystals of different sizes and types. The fascination probably arose millions of years ago.
Small crystals of quartz and calcite have repeatedly been found at archaeological sites next to the remains of early humans that are up to 780,000 years old. “These crystals, a few centimeters in size, had no known use as weapons, tools or jewelry,” explains a team led by Juan García-Ruiz from the Donostia International Physics Center in Spain. “However, hominids appear to have valued these stones as they collected them and transported them from their site to their shelters.” But why?
In the focus of attention
To better understand our ancestors’ fascination with crystals, García-Ruiz and his colleagues took an experimental approach. “Since we obviously couldn’t carry out any experiments with our ancestors, we decided to use chimpanzees instead,” report the researchers. Along with bonobos, chimpanzees are one of our closest non-human relatives. Their evolutionary line only separated from ours around six million years ago. Two groups of chimpanzees from the Spanish Chimpatía Foundation, which specializes in the rescue and lifelong care of primates from poor housing conditions, served as test participants.
For their first experiment, the researchers placed a large quartz crystal and a stone of similar size on wooden platforms in the chimpanzees’ outdoor enclosure. At first the animals looked at both new objects, but quickly only the crystal caught their attention. They took him off the pedestal, twisted and tilted him to look at him from different angles, and finally took him into their sleeping area. Although their interest waned over time, at the end of the experiment they only gave it back in exchange for bananas and yogurt.
(Video: Garcia-Ruiz Lab at DIPC)
Collecting and sorting
In the second experiment, the chimpanzees were given smaller quartz crystals mixed with ordinary pebbles. Within seconds, the primates identified the crystals and began picking them out. Even when the researchers added pyrite and calcite crystals, which have a different shape than quartz crystals, the chimpanzees reliably preferred the crystal-like stones over the pebbles. “The chimpanzees began to examine the transparency of the crystals with great curiosity by holding them at eye level and looking through them,” reports García-Ruiz.
A female carried the pebbles and crystals in her mouth to a wooden platform where she sorted them. “She separated the three types of crystals, which differed in their transparency, symmetry and luster, from all pebbles. We were very impressed by this ability to recognize crystals despite their differences,” says García-Ruiz. Since chimpanzees do not typically use their mouths to transport objects, the researchers speculate that the chimpanzee viewed the crystals as something special that she wanted to hide.
Transparency and form
Taken together, the observations show that chimpanzees are also fascinated by crystals and collect them without having any practical use for them. “We were surprised at how strong and seemingly natural the attraction of the crystals was to the chimpanzees,” says García-Ruiz. “This suggests that sensitivity to such objects may have deep evolutionary roots.”
According to the researchers, both the transparency of the crystals and their smooth, angular shape probably contribute to their attractiveness. Such properties are rare in other natural materials, so humans and chimpanzees could be attracted to this peculiarity. “Our work helps explain our fascination with crystals and contributes to understanding the evolutionary roots of aesthetics,” says García-Ruiz. “We now know that our minds have been circling crystals for at least six million years.”
Source: García-Ruiz (Donostia International Physics Center, San Sebastián, Spain) et al., Frontiers in Psychology, doi: 10.3389/fpsyg.2026.1633599