Rather than trying to learn from books I would suggest looking in on
the Lake Superior Gem & Mineral Club. They meet on the second
Thursday of the month at 7:00pm at the Senior Center at 2014 W. 3rd
Street in Duluth. Their mailing address is 419 Minneapolis Ave,
You will probably find folks with years of experience who will
welcome a new member and be happy to get you off to a fast start. If
you are lucky, your father was collecting Lake Superior Agates, some
of the most distinctive in the world.
For books, go to your library and check out their selection. You can
try before you buy. Most clubs also have libraries.