An encyclopedia of geology that’s less a reference than a journey

Enlarge / An amethyst may make a good metaphor for geology as a whole. (credit: Getty Images)

To outsiders, geology can seem as dull as a rock, with a lexicon just as opaque, but to insiders, it is a limitless source of wonder. Various authors have used different tools to crack open geology’s dull exterior to show non-geologists the sparkling wonders within: Robert Hazen used color; Jan Zalasiewicz used a pebble; and Richard Fortey used a railway journey, for example.

Marcia Bjornerud uses words to unlock the mysteries of geology the way a video game might use gems to unlock a new level to explore. Her new book is a buffet of bite-size chapters perfect for dipping in and out of, read in no particular order. Geopedia is structured like an encyclopedia to the extent that its topics are arranged alphabetically, but it’s written for enjoyment rather than as a mere fact-reference.

Bjornerud keeps the reading light even when serving up expanses of time and space, and she follows each geological ‘dish’ with a chaser of pointers to other entries that may be related, if only tangentially. After “Amethyst,” for example, she suggests “Kimberlite,” a diamond ore, and “Pedogenesis,” the process by which soil is made.