The crystals are small enough to be grasped with one hand, and they appear a faint fluorescent green color in natural light, and the shape is a standard Platonic three-dimensional. There are five types of Platonic stereos, including tetrahedron composed of regular triangles, regular octahedron, and regular icosahedron, regular hexahedron composed of squares, and regular dodecahedron composed of regular pentagons. The crystal shape structure belongs to the last type, which is the most stable structure in Plato's three-dimensional.

There are so many records of meteorite attacks on the Earth, dating back to the Paleozoic Ordovician period 460 million years ago, covering all over the world, with no less than 50 large-scale events and more than 1,000 small events. The old professor looked at some typical events, which were well documented, and it had been proved that the fall was iron ore or iron-nickel alloys.

The old professor narrowed the scope of his search and locked the keywords on "China", "meteorite rain" and "green", and the results were unexpected, and dozens of meteorite rain events about the Qin Dynasty jumped out at once, and he clicked on the top one: In the thirty-sixth year of Qin Shi Huang (221 BC), it was recorded that "rain gold", and the ground turned into stone; It is also said that it is mixed with "greenstone".

The old professor stared at the keywords "Qin Shi Huang", "meteorite" and "green" to continue his in-depth search.

Historical Records. Qin Shi Huang Benji's account of this incident is: "Thirty-six years, Yingfu guarded his heart. There is a falling star in the lower East County, and the land is stone. As for the shape and color of the meteorite, there is no word, but a year after the stone fell, Qin Shi Huang returned to the west.

In addition, the professor also found such information: The First Emperor was keen on the Immortal Dao, and once ordered the Taoist priests of the world to develop elixirs and search for glowstones outside the sky. The result was that the elixir was unsuccessful, but the green stones were found in abundance. So the First Emperor used the stones outside the sky to build an underground heavenly palace, planning to put his dead body in the heavenly palace after a hundred years to be immortal.

However, these records have not been verified by the cultural relics community and are not credible. The old professor changed the keywords to "four-dimensional crystals" and "meteorites", and the result was that there was obviously a lot less information that popped up, but there were also many pages, and the one with the highest repetition rate was a description of the high-dimensional fragments of the universe. But the message talks about the kind of astronomical-scale high-dimensional islands, which wander in interstellar space, like wanderers in the universe. Since the Milky Way is moving in the universe with the solar system at a speed of 160 kilometers per second towards the Hubble Sphere horizon, it is not impossible to encounter those wanderers in the past or in the future. But this is only a theoretical assumption, no one has ever seen a high-dimensional fragment on an astronomical scale, let alone this fist-sized fragment, if it is a high-dimensional fragment.

The old professor did not give up, and looked up some information about the "dodecahedron" crystal, and the answer he got was pyrite and elemental boron crystals, but these two crystal structures were only ordinary dodecahedrons rather than Platonic stereos. Continuing to search for answers, the result is that there is no such thing as a typical Platonic regular dodecahedral crystal in the world, because it does not conform to the principle of symmetry in the law of crystal rotation.

The old professor's inquiry ran into a wall, a wall that stretched infinitely up and down, left and right, a stone that human knowledge could not explain, at least for now.

As the saying goes, the sun rises in the east and rains in the west. Just when the old professor had no way out in the matter of crystals, Miss Sesame's study made a breakthrough.