What are the three strange stones in the Forbidden City?

Wood stone, Zhuge Bai Beidou stone, sea cucumber stone.

1, Mubianshi: Located in the Forbidden City, it is a fossil ornamental stone formed by the long-term action of an ancient tree in nature. It was originally presented by General Heilongjiang to Emperor Qianlong.

2. Zhugebaibeidou Stone: It is a kind of pebble with high silicification degree, and the pattern is composed of gray-white background and light brown. After a hundred years of history, the pattern is still clearly visible, and it is a stone with strong Taoist characteristics.

3. Sea cucumber stone: it is a medium-sized ornamental stone with the same shape as the sea cucumber connected end to end. The crystal of sea cucumber stone is complete. What's more strange is that the stone is covered with hairy thorns and looks awkward.