A few examples of what you can ask Wolfram|Alpha about:
Geological Structure of Earth
get information about a geological layer of earth
compare several layers
identify the layer associated to a depth
get information about a named eon, era, period, or epoch
generate maps of ancient continent configurations
find the geological epoch corresponding to a given time
get information about a mineral
compare several minerals
do computations with mineral properties
get information about an impact crater on Earth
do computations involving crater properties