Some of the rocks and minerals on our planet are really something to look at.  Sparkly.

Colorful. Translucent.

But some of the others are…well,  a little underwhelming. As far as looks go, this little gray rock isn’t winning any beauty pageants. But its value comes from what it  represents, and what it can do.

This is Shungite. It’s a remnant of some of the  earliest life on our planet, and it offers a window into what  Earth was like two billion years ago. We can even use shungite to  make our own lives better, too.

You’re about to look at this little  gray rock in a whole new way. [♪INTRO] Most of the minerals on Earth  are made up of a smorgasbord of different elements - silicon,  oxygen and aluminium, to name a few. But shungite is different. A lot of the time, it’s almost  entirely made of carbon, and there are different subclasses of shungite based on what percent carbon they are.

So shungite is less of a  mineral, and more of a category, since there isn’t a specific  chemical formula to define it. And if that’s not confusing  enough, you can also get ‘shungite-bearing rocks’, which  aren’t themselves shungite, but do have bits of it all scattered through them, like chocolate chips in a cookie. Of course, carbon-bearing  rocks aren’t all that rare.

Coal is the obvious one, and the vast majority of that formed during the Carboniferous Period. Way back then, we had lots of giant  plant life on land, but not a lot of organisms adapted to decompose  those big plants when they died. So instead of rotting away,  those plants just hung around, and eventually the pressure  of everything else above them made the coal we know and burn today.

But the thing that sets shungites apart from all those other carbon-y rocks is their age. Because the oldest shungite deposit that we know of is around two billion years old. Those ancient shungites are  found near a Russian village called Shunga, which is also  where shungite gets its name.

They formed in the Paleoproterozoic  Era, long before plants or decomposers or anything  multicellular had evolved. And because they’re so old,  there’s been a lot of debate over just what kind of living things  all that carbon came from. The shungite-bearing rocks in  Russia are over a kilometer thick, and extend for around 9,000 square kilometers.

There’s thought to be more  than 250 trillion tonnes of carbon contained in this one deposit alone. So some researchers thought  that this was just too darn much carbon to have come  from anything living, period. After all, not all carbon deposits  have to come from living organisms.

For instance, hydrothermal  fluids in volcanic systems can dissolve and concentrate  specific elements including carbon and form them into big, ribbony deposits. But these non-biological  processes aren’t well understood, and they usually result in a much smaller deposit than the scale-tipping Shunga site. On Earth, it’s living things  that have become the masters of the carbon cycle, and there’s plenty of evidence to suggest that the Shunga material is organic.

The thick shungite-containing rocks  are in clear layers that are also interspersed with other rocks like  dolomite, volcanic ash deposits, and finely crystalline quartz  deposits known as chert. We see that kind of pattern in places where marine life dies in big bursts,  gets covered over by sediment, and then more living things fill in that gap. Rinse and repeat a few  times, and you get a sort of lasagna effect with organic  and inorganic layers.

Tasty. And when we peel apart our lasagna  and just look at the shungite, the micro-structures inside the  carbon layers tell their own story. When researchers looked at  the rock through high-powered microscopes, they found  evidence of filaments and tubes– the same kind of structures  that are formed by bacteria.

Plus, the isotopic compositions of carbon in both the shungite and the surrounding carbonate rocks are consistent with biological processes too. So, despite their great age, these  rocks are thought to have been biological in origin after all, formed  from tiny microscopic organisms, and representing one of the oldest organic mineral deposits still in existence. Based on our geological lasagna evidence, we think the layers of  shungite formed in a shallow water lagoon at the edge of an ancient continent.

Thanks to radioactive decay dating,  we know that the oldest layer is 2.1 billion years old, and the  youngest is 1.9 billion years old. And while we know that microscopic prokaryotes had evolved in the oceans during the Archaean Eon… one to two billion years before our  shungite layer-cake started growing we also know that it took a long time for those critters to like,  do anything interesting. All those oldest lifeforms got their  energy from chemical reactions, and they used elements like iron and  sulfur to power their metabolisms.

But these were hard to come by in that wide ocean, so populations stayed pretty teeny. But by the time the Paleoproterozoic got started, bacteria had evolved a neat little  trick called photosynthesis, and that’s when things really started to take off. Using light to power their metabolisms, microbes were able to tap into an  essentially unlimited energy source.

As long as they could see the sun and had some basic nutrients, they could grow and reproduce. And that shallow, sunlit lagoon off  the coast of the ancient Russian continent was the perfect place for  the mother of all microbial parties. It’s still not clear what exactly  caused those happy microbe communities to die off all at once  to create the shungite layers, but whatever it was, it  didn’t just happen at Shunga.

There are carbon-rich deposits all over the world that date to around this same time, with the same isotopic signatures that we see in the shungite. It’s been suggested that this could  represent one of the first mass extinctions on Earth, affecting the  dominant form of life at the time, and leaving its trace as a massive carbon dump in some of Earth’s most ancient rocks. But they didn’t all start out as rocks.

Because as it turns out, the Shunga deposit used to be a massive oil field. After all, the oil that we drill  for and burn for energy came from microbial die-offs too, so these Shunga-era microbes were just doing it before it was cool. As those rock layers were heated  up and buried deeper and deeper, the carbon in the dead microbes was baked into an amorphous oily substance,  which concentrated in layers.

We’re a few hundred million years  too late to find that liquid oil. All that prolonged heat and pressure transformed the oil into solid carbonaceous shungite. And shungite can’t be used like coal either, because the carbon is packed too  densely for it to easily burn.

But that doesn’t mean it  can’t be useful in other ways. Because the carbon inside these  ancient rocks is sometimes arranged in a ball-shaped cage-like  structure called a fullerene. Scientists have made fullerenes such as bucky balls and carbon nanotubes, and they’ve been studied a ton in the realms of materials and electrical engineering.

But they form in nature,  too, and the first place that researchers found these all-natural  fullerenes was in shungite. One of the properties of these fullerenes is that they can trap other elements  inside their carbon cages, so they’ve been used to help purify water. But before you start switching out  your water filters at home with shungite, you should know that the  fullerene cages can go both ways.

Sure, they can trap all those harmful elements, but that doesn’t mean they’ll  hang onto them forever. One study found that untreated  shungite can actually end up releasing harmful heavy metals into the  water it’s meant to be purifying. But even if shungite water filters  have some kinks to work out, the mineral still has a few exciting applications.

There are a lot of industrial  processes that rely on components made of pure or nearly-pure carbon. And since shungite is pretty much just carbon, that means you could use it in place  of a lab-made carbon component. For instance, electrochemical  analysis uses electrodes made of different materials to investigate chemical properties using an electric current.

Normally, these kinds of  applications use electrodes made of an artificial carbon  crystal called glassy carbon. But in 2023, researchers tested natural shungite under similar conditions and found that the purest pieces work just as well as the man-made stuff. That means shungite electrodes  could offer a cheaper alternative to glassy carbon,  which could help researchers test things like new anti-corrosive  coatings and detergents.

The electrodes could also  be integrated into sensors for heavy metals in the environment, and even for drugs in pharmaceutical and clinical settings. Speaking of sensors, scientists  have tested out another really cool potential use  for shungite in construction. The idea here is to turn building materials into their own stress and damage sensors.

When you grind up shungite into a fine powder and mixed it into cement, you  can alter its conductivity, AKA, how well it can pass an  electrical current through it. And they found that when the  concrete binder contained around 40% shungite by weight,  the shungite particles were able to form a continuous conductive  network throughout the material, which allowed electrical currents  to pass through the concrete. This opens up a world of  possibilities for electrically conductive building materials,  including better heated floorings or self de-icing roads and sidewalks.

Not only that, but they found that the material’s resistance to electricity  changes when it gets compressed, meaning that you could essentially  make concrete that alerts people when it gets damaged, even  if that damage is only internal. It’s important to note that these are all still active areas of research, and none of these shungite-powered tech options have come to market yet. But with over 250 gigatonnes of material sitting in the deposits around Shunga alone, there’s plenty of raw material  for researchers to work with.

So these ancient fossils-turned-minerals might just be the key to some truly  futuristic tech someday. And SciShow Rocks Box subscribers can look forward to receiving their own chunk  of shungite in the mail! Every month, we bring you a hand-selected mineral or fossil that’s perfect  to add to your collection, whether you’re a new collector  or a seasoned rockhound.

But we don’t limit the fun  to just the subscribers. We have plenty of fan favorite  minerals for sale on our website, so you can pick and choose  your perfect assortment. Head to complexly.store/rocks  to check it out and get yourself something that really rocks.

Thanks for watching! [♪OUTRO]