Either these types of rocks are opened in a certain way or it is also amazing that the rock was cut exactly where it needed to be to get that image.
Blind luck........Had he cut it 90° away it would never been seen..........
It’s pure serendipity. There are people who go to our regional rock shows with tons of uncut geodes, which they will cut open after you’ve bought one, and one of the selling points is “you never know what’s inside.” And you don’t.
Geodes that are already cut are usually sold as a pair, not a half. The last one my husband bought had a little Herkimer diamond in one half. It was neat.