What are the answer choices?
It's when someone makes a fast and false conclusion because they only know the general idea of the thing they are concluding, and not all of the facts, if that makes sense. It's kind of like a stereotype, automatically assuming that someone is a certain way just because they participate in a certain sport, for example.
A geode is a round hollow rock lines with crystals.
Try to find it here - bit(dot)ly/32TPpvU