The phrase "I don't have a crystal ball" comes from the symbolism of a fortune teller who uses a crystal ball to see the future.
People use this idiom to express that you don't know what is happening next, especially when someone directly asks them about something that will happen in the future.
People use this idiom to express that you don't know what is happening next, especially when someone directly asks them about something that will happen in the future.
They're discussing a new product, but I don't know what it will be - I don't have a crystal ball!