But that brings us to an equally important question: let’s say Spruce Pine is down for a while. How long until alternative sources of high purity quartz are located and brought online?

After all, as I wrote in the book, it’s not as if there’s no high purity quartz elsewhere. It’s more that Spruce Pine has a near unique combination of purity, availability and price. There are mines in Russia and Brazil, not to mention China, which already produce lots of high purity quartz. There are some companies which are able to make high purity quartz synthetically.

Per here: https://edconway.substack.com/p/whats-happening-at-spruce-pine

So difficult but not impossible or anything, China could manage just fine.