Did people in the Song Dynasty love to admire plant "fossils"? Tree-shaped stone: I am a "fake"!

"There is a stone screen in Shu, with small pines naturally formed, 30 to 50 in number, forming a path, which is beyond description..." This is a passage from the "Dongtian Qinglu" written by Zhao Xigu in the Song Dynasty. The stone screen described in the text has a pine forest-like pattern, which is natural and quite ornamental. Just looking at this passage, do you think the stone screen described is a plant fossil? If you see the real object or picture, I'm afraid many people will be more convinced!

Songping Stone

In fact, this kind of rock is called Moshu Stone. Due to its beautiful and elegant pattern, it was also called Songfeng Stone or Songping Stone in ancient times. It can be used as an ornamental stone. Even in less rigorous circumstances, it can be regarded as a gemstone. For example, Sima Guang called it "the jewel of mountains and swamps" in "Reply to Xue Guozhou's Thank You Shiping". But it can never be called a fossil.

Collection of Trees and Stones

Because fossils are the remains, relics or relics of organisms preserved in rock strata during the geological history, or even those invisible and intangible organic chemical molecular structures formed after decomposition. In any case, the first condition is that they are related to life activities and follow the laws of life activities. For example, the branches and leaves of real plant fossils have certain regularity in shape, while the branches on the patterns of simulated tree stones are irregular.

Plant fossils in the collection

Secondly, the formation and preservation of fossils also follow certain rules. Usually, fossils can only be formed in sedimentary rocks. The reason is very simple. The formation of igneous rocks and metamorphic rocks is accompanied by high temperature and high pressure. In such an environment, the buried biological traces will be destroyed, let alone the formation of fossils. However, phyllites can appear in three types of rocks. Moreover, fossils usually follow the formation rules of rock layers and are preserved on the horizontal plane of rocks, but phyllites are very different, with vertical planes, oblique planes, and fissure planes everywhere.

Since it is not a fossil, how did those plant-like lines form? This question can actually be explained by a small phenomenon in life. When we accidentally drop a drop of ink on a paper towel, the tiny fiber structure in the paper towel makes the ink spread on the surface. This is the capillary effect. The same principle, the colloidal solution containing manganese oxide and iron oxide penetrates and diffuses horizontally or vertically along the stratification and cracks of the rock, and gradually settles down. After the liquid dries up, it eventually forms a pattern similar to pine branches on the surface. Some jades, such as the grass flowers in Huanglong jade or agate, are also formed for the same reason.

Although it is not a fossil, it has a natural and realistic tree shape, which makes people sigh that nature's creation is like magic. Calling it a tree-model stone is also a double entendre.