In September 2024, Hurricane  Helene struck the southeastern US,   causing widespread damage to lots of regions  that rarely see storms as severe as this one.

The mountains in western North  Carolina were hit particularly hard,   with entire towns washed away by the flooding. It will probably be months, or even  years before the region fully recovers.

But the disaster could have an unexpected impact   on the rest of the world, too.  Specifically, on our technology. Because pretty much every silicon  computer chip in the world exists   thanks to one mineral deposit in a tiny  town in the North Carolina mountains. [intro music] This story begins about 450 million years ago,  with something called the Taconic Orogeny,   one of the many phases of tectonic activity  that formed the Appalachian Mountains. As two tectonic plates converged,   dense oceanic crust was pushed under  the roots of the continental plate, forming sheets of rock that were thrust over  existing layers, fittingly called thrust sheets.

The friction between these two plates raised the  temperature enough to melt the solid rock below. That molten magma then forced its  way up through the surrounding rocks, creating huge blobs of granite called plutons,   and big cracks filled with  volcanic fluid called pegmatites. When this happens, that volcanic fluid cools  down and the minerals in it form crystals.

The longer this cooling process  takes, the bigger the crystals. And because all this was  happening so deep in the crust, the fluid in the cracks  solidified /extremely/ slowly,   allowing it to separate out  into big, pure mineral crystals. Fast forward a few hundred million years,  and the movement of the tectonic plates   eventually brings the plutons and the  pegmatites closer to the Earth’s surface, in the Blue Ridge Mountains in North  Carolina, near the small town of Spruce Pine.

The pegmatites in Spruce Pine are made  up of about 65% feldspar, 25% quartz,   and 8% mica. As a bonus, there are some gemstones  like aquamarine and emerald mixed in, too. And because of all these great crystals, people  have mined the area for thousands of years.

Historically, Native Americans living  in the region would extract mica and   carve it into figurines or use it as currency. Then, during the late 1800s, Spruce  Pine became a full-on mining town. But the funny thing is, even though nowadays  the region is most famous for its quartz, they were mining out pretty  much everything except quartz.

The big flat sheets of mica made great  stove windows and electrical insulators, and the feldspars were used  in ceramics and glassmaking. Extracting the feldspar involved crushing  up the rock, submerging it in water, and using air to skim off what you want. Everything else, including the quartz,  was considered waste and thrown away.

It took a while for anyone to realize  just how special that quartz really was. See, even though it’s the second-most  common mineral in our Earth’s crust,   not all quartz is created equal. When the crystals grow, sometimes little  impurities get stuck in there, too.

And sometimes that’s considered a good thing, since that’s how we get the fancy  varieties of quartz like amethyst or agate. But the impurities change more  than just the color of the crystal: they can also change its physical and  chemical properties, which can make it weaker. So while amethyst looks great on your bookshelf, it’s less great in the kinds of  industrial applications where   you really need consistency and predictability.

For these applications, high purity  quartz becomes the special sauce. This purity is measured in percentages  of inclusions, or in parts per million. A medium level of purity is considered to  be quartz with 0.1% other elements mixed in, or 100 parts per million of impurities.

While the highest purity quartz has no more than  0.003%, or 30 parts per million of other stuff. And that quartz at Spruce Pine that  people used to think was waste? Well, it turned out that it had fewer impurities  than any other natural quartz we’ve found, at just between 25.9 and 13.4 parts per million.

When the mining companies in Spruce Pine noticed  the purity of their so-called waste quartz, they started selling it,  too. And in the beginning,   it was used to make everyday glass  products, like bottles and windows. It was even used to make a 5 meter wide,   20 ton mirror for a telescope that was built  in the 1940s, and is still in use today.

But Spruce Pine’s quartz really got its  big break with the dawn of the digital age, when the world began to run on  silicon-based computer chips. Today, silicon chips run pretty  much all of our modern technology. They’re in our computers, phones and tablets,  and pretty much anything else that goes beep,   from barcode scanners to wind turbines.

And even in your pets, if they’ve got microchips! To make these fancy chips, the ideal mineral to  use is silicon, because it’s a semiconductor. A semiconductor is just a thing that can either  conduct electricity or insulate against it, depending on the other chemical  elements that are added to it.

So because the exact chemical makeup of  your semiconductor changes its properties, for a consistent microchip product,  you need super-pure silicon. All chips start out as a slice of  a single, perfect, silicon crystal, which is manufactured using something  called the Czochralaski process. It starts with pure quartz sand, which gets  heated up with carbon to remove the oxygen,   leaving behind 98% pure silicon.

Then you do a few other chemical  processes to increase the purity   to somewhere around 0.01 parts per billion. That means that for every hundred billion atoms   of silicon you’ll only have a  single atom of something else. This ultrapure silicon is then  put into a crucible and heated   to precisely 1,413 degrees Celsius  to melt it down into silicon soup.

You then dip a seed crystal of silicon into  the top surface of the molten silicon pool and   drag it upwards, veeery slowly, so it grows  into a crystal of exactly the right shape. The result is a perfect cylindrical  crystal of silicon, called a boule,   with no irregularities and nothing else mixed in. Finally, the boule is cut into circular  wafers roughly half a millimeter thick,   which are polished and made  into countless computer chips.

So this whole thing starts with quartz  and we’ve been obsessed with purity,   so you’d think that the Spruce Pine  quartz is what makes those chips, right? Wrong! See, even though the Czochralski process starts  with quartz, that quartz gets purified a ton   anyway, so you can take any old junky  quartz and turn it into silicon chips.

So you don’t need Spruce Pine quartz to make  the chips. You need it to make the crucible. For those of us who skipped blacksmithing lessons,   a crucible is just a container  that you melt stuff in.

It needs to be heat-resistant enough to  hold your melted stuff, and it also needs   to be made of something that isn’t reactive  and won’t taint that melted stuff, either. They’re usually made of metal, or clay, or  porcelain. Or in this case, extremely pure quartz.

Crucibles for the Czrochralski process are made   by taking ultrapure quartz sand and  heating it up to fuse it into shape. The final product has a melting  temperature of around 1700 degrees celsius. And these crucibles don’t last forever.  Over time, the molten silicon starts to   eat away at the crucible, which is  exactly why it needs to be so pure.

Any impurities in the crucible have a  chance of getting into your liquid silicon,   which could affect how the crystal grows. The purer your crucible, the  less chance of that happening. So it seems like a simple thing,  but the silicon semiconductor   industry really hinges on the supply  of these ultrapure quartz crucibles.

Bad crucibles means bad crystals, no  usable silicon wafers and no… well   anything technological, really. In 2015, it was estimated that we used around  30,000 tons of ultrapure quartz per year,   and up to 90% of that comes from Spruce Pine. Plus in the nearly ten years  since that figure came out,   it’s almost guaranteed that that number’s gone up.

Not bad for a town with just 2500 people! But that’s ultimately what makes  the situation so precarious. It’s   a single point of failure for a  multi-billion dollar industry.

Which brings us back to the storm that got  so many people talking about this place. Hurricane Helene struck Spruce Pine in  the early hours of September 27th 2024. It had been downgraded to a tropical  storm by the time it got there,   but the storm still did a  surprising amount of damage.

Roads and buildings were destroyed or washed away,   and thousands of people lost  power or water to their homes. As of this recording , there are  at least 96 confirmed deaths,   and dozens more who are still missing. And because of all this devastation,   the quartz mines have shut down,  and only one is back up and running.

Meaning that the world’s supply of ultrapure  quartz will be impacted for as long as the   other mine is down, and possibly for longer  as they both try to make up for lost time. Now, there are some other deposits of  ultrapure quartz in places like Russia,   China and Brazil, but none are quite as pure  or as plentiful as the quartz from Spruce Pine. And while it’s technically possible to  purify lower-quality quartz or to make   synthetic ultrapure quartz, nobody’s really doing  either of those things at an industrial scale.

They’ve never had to, because Spruce  Pine quartz has always been there. Until now. To be clear, there isn’t any reason to panic and   start hoarding silicon chips  like toilet paper in 2020.

Plenty of companies have stockpiles of  silicon wafers for situations just like this,   so the mine being closed isn’t an immediate  problem for computer chip production. But if mining is down for more than a few  months, and that stockpile becomes depleted,   then we could be looking at a major supply  chain issue for basically the whole tech world. The last time something like this  happened was during the pandemic,   when everyone realized they didn’t want  to be stuck inside without a screen, and demand for tablets, computers and consoles  temporarily but expensively outstripped supply.

But this time it would be the other way round.  The world would still have its everyday demand for  computer chips, but the supply would be the issue. As availability of the remaining  wafers diminished, prices for   all tech could skyrocket, not just the  stuff you can watch YouTube videos on. And we don’t know how bad the problem really is.

Ultrapure quartz mining is a secretive business,   so the mining companies have thus far been  pretty cagey about just how bad the damage was. For now, we’ll just have to  sit tight, and wait and see. It’s kind of crazy to think about how every  piece of technology we use, from microwaves   to TVs and cell phones to singing greeting  cards, could only exist because of one place.

One weird quirk of geology when  two plates collided gave us the   exact ingredient we needed to be  able to make any of this possible. So thanks Spruce Pine, for being  the unofficial partner and sponsor   of basically everything we’ve ever  looked at on a screen. We owe you one. [Outro music]