This is my second time living in Idaho and it's not like I was here for three years and then left and never came back. Even though I didn't live in Boise I was here a lot, my point is that I've been in Idaho consistently for the last ten years and believe it or not in the last 10 years I've never asked myself or for that matter anyone else " Why is Idaho called the Gem state?". There are a few new people that just started working at the station and have moved here from elsewhere, today one of them asked me that very question... Well according to quora.com :

"Idaho is known as the "Gem State" because the only other location on the planet which has a greater variety of gems is Africa. More than 72 different kinds of precious and semi-precious stones can be found throughout the state, particularly in mining sites and stream beds."

Interesting for sure, you just learned and Idaho fun fact. You're welcomed.