(ORDO NEWS) — On Gandang Mountain, located in the southwestern region of China, there is an interesting phenomenon that geologists, researchers and locals have been observing for several decades.
In the rocky walls of the base of a mountain located in Guizhou Province, there is a cliff that the locals call “Chang Dan Ya”, which means “egg-laying cliff” in Mandarin, due to its ability to “lay” stone “eggs” every 30 years. But where do they come from?
The cliff of the mountain that lays the eggs is approximately six meters (20 feet) wide and 20 meters (65 feet) long, which is rather small compared to the size of the entire mountain.
Approximately once every 30 years, a small rock “lays” a stone egg on its side. As soon as the stone egg breaks off the cliff, it falls to the ground, where it can be found by the first local resident who is lucky enough to stumble upon it.
This phenomenon of laying stone eggs has been observed for hundreds of years. The locals of this region have heard stories of the mountain that lays eggs since childhood, and most of them, having matured, go there to try to find the fallen stone egg.
The size of the found stone eggs varies from 20 to 60 cm (7-24 inches) each. They have a dark blue tint and are almost perfectly smooth, allowing them to reflect sunlight at a certain angle after being cleaned and polished. The largest stones, as it turned out, weigh more than 600 pounds (272 kg)!
The closest village to Chang Dan Ya is Gulu Village, an old district in Sangdu Shui Autonomous County, home to 250,000 Shuis, more than 60% of China’s population.
The Shui are one of the 56 officially recognized ethnic groups in China and have been living in the region since before the Han Dynasty. Although the region itself is large, the village of Gulu is actually quite small, with only a few dozen families living in it.
The name Shui can be translated as “water“, which is quite appropriate given their history of living near water. Whether it is rivers or streams, the Shui people can be found living near them.
At some point in history, several Shui communities were forced to move to the mountains, where they live to this day, preserving their love for water. Their traditions, folklore and other beliefs revolve around the concept of water.
Most of their clothes are dyed shades of blue to match the color of the water. In fact, the Shui language was also designed with water in mind, as there are ten different words for “fish” in their language.
Since the local egg-laying mountain was discovered, locals have reported that over 100 eggs have been found at the base of the rock. Currently, about 70 are in the village and are divided between families depending on who found them first.
The rest, they said, were either sold or stolen. The people of Shuya believe that stone eggs, born from the mountain that lays the eggs, bring good luck and fortune, and even sometimes worship them.
They can be found in almost every house in the village and are highly respected by those who collect them, as they are believed to bring prosperity and security to people, animals, and homes.
The formation of these mysterious stone eggs is still being studied. Based on current research, it is believed that these eggs and the surrounding rocks in this region were formed during the Cambrian period about 500 million years ago.
The Cambrian period was part of the Paleozoic era and is known for the “Cambrian Explosion” – the period of time during which, according to the fossil record, most of Earth‘s major animal groups arose and diversified.
Geologists speculate that the region was once under water, which may have contributed to the formation of these egg-shaped rocks over time.
It is believed that as a result of heat and compression on these stony eggs over the past 500 million years, they have come to be considered metamorphic rocks.
Metamorphic rocks are formed from existing igneous or sedimentary rocks that are subjected to intense heat and pressure underground over an extended period of time.
Professor Xu Ronghua of the Institute of Geology and Geophysics at the Chinese Academy of Sciences claims that the stone eggs are made from silicon dioxide, which must have been present in the region during the Cambrian period.
If this is true, then, he says, the ovoid shape of the rocks makes sense – since the sphere has a small surface area compared to other shapes, the silica particles would have to cling to form a sphere in the water before being compressed into metamorphic rocks.
Being underwater also contributed to the roundness and smoothness of the stones. As the rocks move along the ocean floor under the influence of surrounding currents and animals, they are worn away, becoming smoother and more rounded. The same concept applies to making ocean glass or homemade rock tumblers.
Silica is present in many rocks, with some rocks having more of it than others. The fibrous varieties of silicon dioxide are called chalcedony. Examples of chalcedony are agate, bloodstone, and onyx.
Quartz and moganite are also composed of silica, but each has a different physical crystal structure than all the other examples.
It is not entirely clear why rock eggs are black and not transparent, milky or pastel like other flint stones, but scientists are actively trying to uncover further secrets about the composition of these mysterious rock eggs.
The area surrounding the rock outside of the eggs, however, is different. The cliff itself is not composed of metamorphic rock. Instead, the surrounding rock is composed of calcareous rock, which is considered to be sedimentary rock.
Sedimentary rocks can be found closer to the earth’s surface and are composed of compacted deposits such as sand, soil, or small pieces of rock.
Examples of sedimentary rocks are limestone, sandstone and shale. These sedimentary rocks surrounding the stony eggs may have contributed to their compression and separation during the last 500 million years.
Although it may seem that stone eggs take 30 years to form and are “born” on the side of a rock, this is actually not the case. As stated earlier, these stone eggs are thought to have been around for about 500 million years.
Over time, the rocky slope of Chang Dan Ya has worn out as a result of weathering and erosion. Changes in temperature and the effects of wind, water, ice, gravity, humans and animals can eventually erode even the largest rocks, including mountains.
Since the composition of the stone eggs and the surrounding rock differ from each other, it is believed that the surrounding rock simply wears out faster than the stone eggs themselves.
This is because calcareous rocks break down faster than metamorphic ones. Lime rocks are mainly composed of calcium oxide, carbon dioxide and magnesium oxide.
They may also contain trace amounts of aluminum, iron, silicon and water. The surrounding sedimentary calcareous rock, due to its composition, breaks down faster, exposing stony eggs of a different composition over time. Since the Metamorphic Stone Eggs do not break down with the surrounding cliff, they fall out of it as they wear out.
Locals in Gulu have calculated that it takes approximately 30 years for each stone egg to “lay” from the moment it first appears in the rock until it falls to the ground.
A stone egg that is just emerging may lie for another 30 years before the rock is weathered enough to fall, and a stone egg that has already been partially laid may lie for only 10 to 20 years.
Since all the stone eggs are in different places on the rock, the egg could theoretically drop at any moment for the next lucky person to find it.
As the mountain continues to erode, stone eggs may begin to appear on the paths frequented by Shui locals and other tourists. If this happens, it may be difficult to travel by footpaths or on horseback, and steps must be taken to physically remove or destroy protruding eggs.
What awaits the famous egg-laying mountain? As the slopes of the mountain erode over time, more stone eggs will come out of the rock and fall to the ground. In addition, the eggs may begin to protrude from the top of the mountain, as it is eroded by foot traffic, as already mentioned.
Geologists can’t say exactly how many eggs are left in the mountain, but they could theoretically be all over the mountain if there was enough silica in the region during the Cambrian period. Ultimately, no one will know about it until the mountain runs out of stone eggs – if that happens at all.
Over the next few thousand years, the mountain will continue to erode into the soil, leaving behind these eggs. If the eggs are no longer collected, they will remain on the ground, where they too will break down and turn into sediment, from which new sedimentary rocks will eventually form.
This is the cycle of rocks that we all learned about in elementary school. However, without being exposed to weathering factors such as soil, wind, water and ice, stone eggs can be preserved by humans much longer if they are carefully collected.
Believe it or not, this particular cliff at the base of Chan Dan Ya is not the only area that “lays eggs”. In other, less frequented areas of the mountain, outcrops and discards of eggs are also observed, suggesting that the entire mountain is full of them. If this is true, then locals may see more of these unique stones for generations to come.
Families in other nearby areas may also start collecting these eggs as they become available and use them for trade, tourism, or religious purposes. Those who live on the other side of the mountain and have never seen the egg-laying phenomenon before can begin to observe it themselves.
Although Gandang Mountain was the first place where these stone eggs were discovered, it is possible that other places may exist in unexplored mountainous areas.
It is also possible that mountains may contain more stone eggs in the future. Our oceans currently contain 30 ppb (parts per billion) silicon dioxide, and the earth’s crust is 59% silicon dioxide.
Since such a large amount of silicon is still present both in the earth and in the oceans, it is possible that future mountains may contain newly created eggs in a few million years. While we won’t personally see these mountains lay their eggs, perhaps those who see it will be just as fascinated by it as we are.
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