Geologist on the Moon
The only Apollo astronaut to visit the Moon who was a qualified geologist was Harrison H Schmitt:
https://www.nmspacemuseum.org/inductee/harrison-h-schmitt/?doing_wp_cron=1675689989.5584039688110351562500
"The Lunar Module pilot on Apollo 17, the final manned lunar landing mission, Harrison H. Schmitt, a geologist, and native New Mexican, is the only scientist to have explored the Moon’s surface."
It does seem like a good idea that if you are interested in finding out about planetary science and sending people to other worlds that they should have expertise in geology.