We like rocks, especially pretty rocks.

And humans also like categories. So, it should come as no surprise that somewhere, someone thought it was a good idea to assign a bunch of the prettiest rocks  to the months of the year.

The history of birthstones actually  traces back more than a millennium, through multiple religious traditions. And the tradition of associating them with months of the year goes back centuries. But most of the month gem  pairs that get brought up when people talk about birthstones come from a list created by the  Jewelers of America in 1912.

And even though the list probably  began as a marketing tactic, people love their birthstones. Well, a lot of people do, anyway. Others wish they’d been  born just a few days later… But while most people love  them for what they represent, a lot of the birthstones  have actual practical uses.

So let’s run through all  twelve months of the year, and see which stones do more than look pretty. [Intro music] The most famous color of January’s  stone garnet is a deep blood red, but it can come in quite a few colors. And just like those color  options, garnets are versatile when it comes to applications. But before I get into any  applications for any birthstone, I should note that a lot of the time, lab-grown is best, a lot better  than anything we get from ground.

They’re predictable, cheap, can be  made with certain color properties, and can be guaranteed to come out flawless, which is often crucial. But sometimes you can get away with  the stuff you get out of the ground. Natural garnet works just as  well for our first application: filtering water.

That’s because garnet is a  relatively hard material, which helps make it super  durable and resistant to erosion. You can also make it into very, very small grains, so you can filter out teeny tiny particulates. Garnet water filters can remove  particulates down to 10-20 microns.

For context, that’s contaminants between the sizes of red and white blood cells. These gemstones are also used in  devices called scintillation detectors, which are used to detect ionizing radiation… the kind of radiation we usually worry about. They’re so well-suited for this task because they glow if you hit  them with a lot of radiation.

And to round out our list of garnet applications, we can use them in some specialized lasers. But there’s another birthstone with a  much closer relationship with that tech, so you’re going to have to wait  until July for that discussion. For now, we’ll move on to February.

Next up, we’ve got amethyst. Which is an admittedly lovely  gemstone, it’s my birthstone, but as far as practical uses go, it doesn’t seem to have all that many. That said, amethyst is type of quartz, which is very useful.

I mean, it’s in everything from countertops, to insulation, to clocks. Plus, quartz has piezoelectric properties, which means it can generate electricity when you apply some kind of mechanical stress. But amethyst itself doesn’t  have a lot of unique use cases.

We did find one paper from 2011, which proposed amethyst ore could  be used as a radiation shield, because we know amethyst  absorbs ionizing radiation.. In fact, that’s actually what  turns the crystals purple. But so far, that paper was an isolated proposal.

For now, you February babies will just have to be content with those massive amethyst  geodes they stick in museums and rich people’s homes. March’s gemstone aquamarine might share its name with an iconic movie mermaid, but it isn’t much different from amethyst when it comes to usefulness. Aquamarine is a type of beryl, which is mostly useful as a  source of the element beryllium.

And beryllium is one of those elements  that’s found all over modern tech. The metal is pretty scratch resistant, and it  stays pretty stable at a range of temperatures, so it’s great for some very  high-tech applications. For example, it’s what we used to make a bunch of the pipes we accelerate all the particles  through in the Large Hadron Collider.

And it’s what we made the mirrors on the James Webb space telescope out of beryl is also a carcinogen, meaning it’s cancerous if inhaled. So maybe leave collecting the beryllium in it to the professionals Next up is April. In terms of gemstones, diamond is about as useful as you can get.

There’s no way we’re getting through even a fraction of its uses in this video, so we’re gonna have to settle for  highlighting a few particularly cool ones. Most famously, diamond is the hardest material that occurs naturally on Earth. For a long time, it was the top  of the hardness scale period, although some recent developments  have called that into question.

Regardless, diamond is incredibly hard, which makes it great for  things like drill bits, files, and specialized cutting tools. But there are even cooler applications, like anvil cells. First created in the 1950s, anvil cells are devices that  scientists use to generate massive amounts of pressure in  highly localized environments, allowing them to study the  effects of intense pressure.

At their absolute basic level,  diamond anvil cells consist of two diamonds, a sample,  and, for lack of a better word, a smushing apparatus that the diamonds sit in. The diamonds are each cut into  that stereotypical diamond shape, but with the little point flattened out. And then, they’re placed into the  smusher non-point to non-point.

Once everything is in place, the sample gets placed very  carefully between the two gems. And the researchers channel their  inner Queen and David Bowie. This is an Under Pressure joke As pressure is applied to the  wide top faces of the diamonds, it essentially funnels down and gets concentrated at the little non-pointy surfaces.

This generates MASSIVE amounts of pressure right between those two surfaces. Like, core-of-the-Earth-type pressures. Now, diamond isn’t the only material  that scientists use to make anvil cells.

But it does have one major advantage: light passes through it. That means with a diamond anvil cell, you can see inside your experiment  the whole time you’re running it. Pretty cool bonus.

It also means that, if you want to, you can  shoot the whole contraption with lasers to heat the  sample and see what that does. Good thing diamonds can also handle a lot of heat. But diamond anvil cells are old.

Is there anything new that diamonds can do? Well, yeah. The newest of the new, in fact.

As it turns out, diamonds might  be great for quantum computing. If you go into the molecular  structure of a diamond, replace one carbon atom with a nitrogen atom, and leave a neighboring atom spot blank, you get what’s called a nitrogen-vacancy center. Electrons can then temporarily  fill the slots in that gap, and interact with the carbon  atoms in the rest of the diamond.

This allows both atoms and electrons to function as the quantum computer’s  version of bits, called qubits, while the diamond lattice  holds the whole thing together. And while you might not think the words “diamonds” and “affordable” go together, this actually might be a  fairly inexpensive solution for creating a quantum computing system that keeps working for an extended period of time, and at room temperatures too. So, honestly, when it comes to a diamond, the better question is what can’t it do.

Anything is gonna be a step  down in usefulness from diamond, but May’s emerald is… kind of a big one. Emerald is another type of beryl, so it  has all the cool aspects of other beryls. And it can be used in lasers, but from what we can tell,  it’s not all that popular.

But that’s kind of it. Sure is pretty, though. Next!

June’s birthstone is pearl.  And, to be honest, pearl is kind of a  weird one in the usefulness department. Because they’re definitely useful…to  the animals that make them. Pearls are made when a  creature surrounds an irritant with a smooth substance over and over again, to protect itself from cuts  and other forms of damage.

They can even do this to whole fish, which just looks wild! But for humans, the practicality of  pearls is a bit less straightforward. People have long suspected that  they might have health benefits, which actually applies to a  lot of the gems on this list.

Across time and cultures, humans tend  to think “pretty” and “beneficial” go hand in hand. For example, Traditional Chinese Medicine  has used pearls for millennia. But there’s little to no significant modern, Western evidence that supports medicinal use.

That said, June doesn’t have to count itself  out of the Useful-lympics entirely, because it has an alternative birthstone: alexandrite. And alexandrite has a few more applications. Alexandrite is a super rare form of chrysoberyl… which, despite its name, is not a type of beryl.

Its most common scientific use case is in lasers, specifically dermatological ones. Alexandrite lasers are very commonly used in things like laser hair removal, tattoo removal, and leg vein treatment, because  the light it produces gets absorbed by the melanin in our skin so well. And on top of that, there’s even some experimental  alexandrite laser usage in dentistry.

Not bad, June. And now that we’ve hit the  halfway point in the year, we’ve got to keep the lights on with an ad This SciShow video is supported by

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If you’re a young professional in the   pharmaceutical industry or  countless other industries, you can visit jmp.com/scishow to reap the  benefits of visual statistics for yourself and get a 30-day free trial. July’s birthstone is ruby, a.k.a. the red version of  a mineral called corundum. And this is another mega-useful gemstone.

It’s also where we’re finally  gonna talk about lasers, because rubies and lasers are deeply intertwined throughout scientific history. In fact, the very first laser used a ruby crystal! Lasers work by taking advantage of  what’s called stimulated emission.

So let’s unpack that a little bit. Atoms generally want their electrons to exist in the lowest-energy level possible. I mean, as much as atoms  can “want” anything, anyway.

But if you blast them with photons that  have just the right amount of energy… that is, light that is just the right color… those electrons will absorb  that energy, get excited, and jump up to a higher energy level. Then, when the electron eventually sheds  that energy to drop back to its base level, it has to emit its own photon. This process is called spontaneous emission.

To achieve stimulated emission, you basically have to get your  atoms to stay excited long enough by shooting them with even more photons through a process called pumping. And when they drop back down to the ground state, they’ll produce more than one  photon of the same wavelength, amplifying whatever photons were  originally blasted into the system. But this pumping is only  possible in certain materials… specifically, ones where you  can “tune” the energy levels so that they absorb and emit  photons of the right wavelength.

If your material doesn’t work  that way, you can’t pump it, and you can’t make it amplify  light like a laser does. Lucky for ruby-lovers, the  gem works perfectly for this. However, lasers are far from the only place you’ll find rubies doing actual work.

For example, they’re  sometimes used in watchmaking. Corundum in general is super hard and doesn’t generate a lot of friction, so rubies can keep metal parts  from wearing each other out. They also fluoresce, or glow,  differently under different pressures.

This allows them to be used with  those diamond anvils from earlier to measure exactly what the  pressure is inside the diamond cell. I could go on, but July’s had  enough time in the spotlight. Peridot might be the most  controversial birthstone.

Some August babies love it; some hate it. And some grew to hate it less after they learned more about the science related to it. Peridot is a nicer version of  one of the most common minerals in Earth’s mantle: olivine.

So, it’s useful for all the reasons  any other kind of olivine is useful. It’s been found in meteorites and on the Moon, so scientists can study those samples and tinker with Earth olivine to better understand  planetary science more generally. But olivine is also useful  in certain industrial cases, like steel manufacturing.

It’s even been proposed for use in  electric vhiecle battery cathodes and even carbon sequestration, which is the process of pulling (carbon  dioxidite) CO2 out of atmosphere. So from the August babies who worked  on this script: thanks peridot, for being the more useful of  the two green birthstones. Just like ruby, September’s birthstone  sapphire is a type of corundum.

In fact, pretty much all corundum that isn’t red gets labeled sapphire. So it should be no surprise that  sapphires have a bunch of different uses. For example, sapphire can be used as a substrate, meaning that you can grow things on top  of it.

But not “things” like plants. “Things” like semiconductors and  microelectromechanical systems. Say that 5 times fast There’s a whole class of these “things” that are just referred to as silicon-on-sapphire. As the name suggests, they’re made by growing a very thin layer of  silicon on top of a thin piece of sapphire.

Meanwhile, sapphire is also  used in some fancy timepieces, but for a different reason  than their ruby siblings. White sapphire can be cut in such a way that it basically functions  as super durable glass. People use it as watch faces to  protect all the delicate gears inside.

You know, in case you whack  your wrist against a chair you thought was a little further away  which I have obviously never don). Some scientists are even looking into replacing the glass of smartphone screens with sapphire. But that’s not even the  most high-tech application.

By combining sapphire substrate,  see-through optical materials, and high-tech gadgetry, you can make the thinnest lenses in the world. They’re just a few atoms thick! And one day, they might be used in the  pinnacle of Augmented Reality eyewear.

Personally, I’m going to avoid any tech  that reminds me of the Google Glass days, but I’m sure someone else is going to love it. And anyway, I’m way more  interested in October’s entry: If you know anything about gemstones, you might not think that  opal would be very useful. It’s not super durable or super clear, which are the two main properties that  make most gemstones useful on their own.

But with opal, the lack of  clarity is the whole point. Opals are natural versions of what  are known as photonic crystals. And to explain what that means, I need you to picture something for me.

You know when you put a straw in a glass of water and it looks like the straw bends? That’s because air and water have  different refractive indices, meaning that light travels  through them at different speeds. Photonic crystals are special because their refractive index changes  periodically throughout the material.

Their crystalline structures have  little holes in between particles, and those little holes have  different refractive indices than the rest of the structure. And every time a ray of light  enters a different medium with a different refractive index, a portion  of it bounces off instead of getting bent. In a natural opal, this scattering  leads to all the sparkly colors you see.

But if you build a version of a photonic  crystal very carefully in a lab, you can control how all those  little scatter-y bounces work. And, if you’re very careful, you can even  get all the reflected light to add together. This behavior has earned artificial  photonic crystals a reputation or being incredibly good mirrors.

So good, in fact, that some can reflect  more than 99% of the light that hits them. Scientists have used them in things like surgical laser scalpels and solar  cells to make them more efficient. But based on early research, they might also prove useful for  telecommunications for the same reasons.

Now, technically, a lot of this  tech is still fairly cutting edge… pun intended. But it doesn’t seem like we’ll be seeing  the end of opal’s usefulness anytime soon. November has a few options for its birthstone, but we’re going to focus on topaz.

It has a few applications, one of which requires very specific circumstances. Very, very hot, specific circumstances. Topaz is heat resistant, hard,  chemically stable, and wear-resistant, so slabs of the material  are super useful in things like kilns and furnaces that are  basically mega-heat containers.

You can also mix it into substances like cement to give them a boost in the  direction of topaz’s cool features. And on top of all that, it might  also be usable in dosimetry, which is the process of detecting radiation. So the uses are pretty niche,  but topaz is definitely useful.

And last but not least, we have December. Another month with a bunch of birthstone options… which thankfully lets us skip over turquoise, because it’d be a bit of a flop to end on. Lapis lazuli is one of the month’s birthstones, which has been used as a stunning  pigment throughout history.

But we’re gonna focus on zircon, because zircon is where it’s at for uses. It’s used in high-heat environments like topaz, but even more extreme ones. And much like beryl is the source of beryllium, zircon is humanity’s primary  source of the metal zirconium.

Zirconium is used to make everything from ceramic knives and sandpaper, to vacuum tubes, old photography flashbulbs, and nuclear reactor fuel pellets. But I would argue that zircon’s  coolest use is in planetary science. Because zircon is super robust, its crystals can withstand billions  of years of geologic processing.

The rocks surrounding tiny  zircon grains may change. But zircons itself doesn’t. The oldest zircon crystals we’ve found  are roughly 4.4 billion years old.

Our planet is 4.5 billion years old! So zircon doesn’t just provide a window to the earliest moments of Earth’s history, it helps geologists track  the evolution of our planet… how it got from a ball of molten  rock and metal to what it is, today. Not bad for a relatively  boring-looking gemstone, if you ask me.

Not bad for the whole list, if we’re being honest. It’s pretty cool that  birthstones can do a lot more than adorn our rings and necklaces. Although a few of them do  look pretty good on a shelf displaying samples from the  SciShow rocks box collection. [ OUTRO ]