Taken by themselves, geodes are gorgeous, with the insides lined with crystals that add a sense of beauty and wonder to the rocks, and they become even more amazing when they are dinosaur eggs, as was the case of a recent discovery in eastern China.
The fossils also happened to be a new species of dinosaur eggs called Shixingoolithus qianshanensis, part of a larger family of eggs found across China.
The palaeontologists do not know what species of dinosaurs the eggs would have produced, a fairly common occurrence in the field, meaning the eggs get classified into something called oospecies.
This allows scientists to document the difference between dinosaur eggs without necessarily needing to know anything about the dinosaurs they contained.
The eggs were discovered in a portion of Anhui province with small mountains that feature large rock features. Scientists had previously found three eggs in the area.
Two of them were housed at the Geological Museum of Tianzhu Mountain World Geological Park, while the third is currently missing.
The scientists wrote in the Journal of Palaeogeography, a peer-reviewed publication, that the discovery “extends the palaeogeographic distribution of the [family of fossil eggs].”
One of the fossilised eggs was broken in half, creating a spectacular geode display. The other egg was in better shape, and while it contained geodes, they were not as stunning as the broken egg.
By analysing the eggs, the scientists felt confident it was similar to other Shixingoolithus but different enough to represent a new species.
While prehistoric eggs that become geodes are rare and exciting, they are not entirely unheard of.
In 2017, researchers going through fossils at the Smithsonian Museum in Washington DC, stumbled upon 50-million-year-old crocodile eggs that had transformed into geodes filled with quartz crystals.
Geologically speaking, it makes sense that dinosaur eggs could become geodes.
The special rocks are formed when air pockets are filled with water. The water brings with it minerals that remain inside the rock after the water evaporates.
Geodes begin to form when this process repeats itself over thousands or millions of years. This is why geodes are commonly found in volcanic rocks, where air bubbles are more common.
The colours, such as the soft milky-white colour found in the Chinese dinosaur eggs, are specific to the type of mineral left inside the rock.
This article was first published in South China Morning Post.