Crying Obsidian

Mystery block refers to an abandoned project by Jeb to implement a change-spawn obelisk.

Jeb has said that this texture will be replaced by the grass-side texture in the 1.5 update.

Currently, it can only be found in the form of a texture in "terrain.png". This texture has been added in Beta 1.3 but is currently not used in the game. It closely resembles obsidian, mostly due to the matching colors. It also appears to be a sandstone texture modified to look like obsidian. There is no indication yet as to whether this texture will be implemented in the future, but as of Beta 1.4, beds can set a person's spawn point, so the block may be used for a different purpose or not at all.

It is also known as "Bleeding Obsidian", "Crying Obsidian" and "The Meteorite" among many members for its appearance.