“Spruce Pine, it turns out, is the source of the purest natural quartz—a species of pristine sand—ever found on Earth. This ultra‑elite deposit of silicon dioxide particles plays a key role in manufacturing the silicon used to make computer chips. In fact, there’s an excellent chance the chip that makes your laptop or cell phone work was made using sand from this obscure Appalachian backwater….”
— From “The Ultra-Pure, Super-Secret Sand That Makes Your Phone Possible” by Vince Beiser in Wired
Fascinating story! And it even mentions the bunkers at Augusta National.