A view across housing-land to the Boise Front. Just over those mountains is the edge of the Idaho Batholith. It's really a huge mass of granite and if I remember right, it's key to the state's nickname of "Gem State." That granite was on top of a moving mass of hot earth and there were cracks that allowed gases and liquids to run through the granite. Those became gold, silver, copper - and - jasper, jade, opals, tourmaline, zircon, and topaz. Those are some of Idaho's gems, and they're mainly found in the batholith - which stretches through most of the central part of the state.