What stone is black outside Venus?

It's black outside, gold inside and obsidian. Obsidian, also known as Jinsha obsidian, is a kind of obsidian with bright gold substance. Obsidian is formed during the rapid formation of volcanic lava, and the rock flow and debris ejected from the volcano are rapidly solidified and hardened. Obsidian is considered to have the function of resisting and absorbing negative energy and protecting the body, and is often used for divination and predicting the future.