Ruri Rocks (瑠璃の宝石)

Mmm! So good!

Don't forget, we still have to eat dinner later.

I'll be fine!

Enjoy it while you're still young...

Imari, you're still young, too.

I dunno, I've been really scatter-brained recently.

You gotta remember to take breaks every once in a while.

Totally!

Besides, this hot springs trip is all thanks to you!

Whoa! It's so big!

Look Up, Examine, Search! And Next!

Look Up, Examine, Search! And Next!

Wow, this is amazing.

Not too shabby.

Look at this coffered ceiling!

Must have been inspired by the eclectic pseudo-Western architecture!

And all these intricate details—

Looks like the entire inn was designed that way.

What an amazing place!

Senpai, let's go look around!

Come on! This way!

Whoa, wait, Imari!

Imari-san can get a little too excited sometimes.

Think so? I can't wait to become a college student like her.

I could spend all my time on stuff I like.

Well, you actually have stuff you wanna do.

I wish I did, too.

But we had fun making that crystal radio.

Yeah, but it's finished already.

Come to think of it, Nagi-san and Imari-san might have my ideal life.

What do you mean?

Well, they're smart and they have ambitions.

Wow, look! It's from the Meiji era!

I bet they have fun all day with nothing to worry about.

I doubt their lives are that easy.

What about you, Tanigawa-san?

Have you thought about your future or career path?

Hey! Look, Seto-san!

Tada!

Vacays get real once you wear a yukata.

Sure, I guess. So back to what I was saying—

All right! Time for us to explore the inn, too!

W-Wait, um, Tanigawa-san!

I can't help but stop and look at rocks.

Same here.

You guys out exploring, too?

Nagi-san!

I found something cool.

Wanna guess what this is?

I dunno, it looks milky?

White and kind of pretty, but...

Why is it shaped like a donut?

I happened to find it roaming around the inn.

Senpai! There's a Taisho era bath this way!

Whoa!

H-Hey, Imari!

It's this way! Follow me!

She said she found it at this inn.

I see some white rocks here, but...

Those aren't milky like this one.

I'm more curious about this shape than the color.

It doesn't seem natural. Could it be man-made?

What could be this size and have a round hole?

Hmm...

A drain?

That looks way off.

What about a statue?

Could it be from the garden?

It's not this, either.

If it's not here...

Maybe it's not from outside.

This must be where Nagi-san found it.

So its shape was from this pipe.

But what is it?

Ruri!

Wow, you two found it yourselves?

Nagi-san! We found the rock in here, but what is it?

If you wanna know, I can take you to where it was made.

This is awesome!

It said it helps with circulation, so it might boost metabolism.

I could stay in here forever.

Nothing beats outdoor hot springs.

Oh yeah, I almost forgot. So, where are these rocks?

Right here.

Huh?

That rock was created by this hot spring.

I can tell there's something mixed in here,

but how can hot springs make rocks?

What's the main material?

Just the hot spring.

Or you could say that the hot spring is the rock itself.

Ground

Hot springs are a type of groundwater.

Groundwater

Groundwater contains dissolved minerals from the rocks it flows through.

Underground

But when groundwater reaches the surface, temperature or pressure changes.

Temperature/Pressure Decline

Oxidization

Or components oxidize, causing substances to return to solid form.

Solids

It turned white! This turns to rock?

Yup.

So that pipe was actually clogged with this white stuff.

m 0 0 l 230 0 l 230 215 l 0 215

Known as hot spring deposits, these accumulate on everything the water touches, such as pipes and bathtubs.

m 0 0 l 230 0 l 230 215 l 0 215

What builds up depends on the composition of the hot spring.

I found a discarded pipe, so I asked the inn if I could keep it.

Once it turns solid, pipes can get clogged as soon as a few months.

That must be difficult to manage.

What kind of rock is it exactly?

I'm assuming mainly lime.

Hot spring water varies depending on the local geology.

By studying it, we can learn what's occurring underground.

Magma

Some hot springs come from rainwater that gets heated over a few decades.

Others are derived from fossil water that's been trapped underground

Fossil Water Water-impermeable layer (such as clay)

Magma

Magma

for tens of thousands of years.

High geothermal heat

Mantle

m 0 0 l 230 0 l 230 215 l 0 215

Oceanic Plate

Ocean

Water

Some also come from ancient seawater squeezed out of ocean plates underground.

Rises toward surface along fault

That can take millions, even over ten million years.

Ten million?!

Hot springs like that exist?

Totally, and guess what?

We're literally in one right now.

This hot spring even contains a small amount of magma.

In cases where water gets squeezed out of the plate,

Water

if it occurs too deep in the plate, the heat becomes

so intense that the rock melts and forms into magma.

Magma

Up to ten million years

Pressure

Pressure

As the magma eventually cools and hardens,

Water

the water separates out, which is called magmatic water.

Magmatic Water

Rises toward surface along fault

I had no clue magmatic water even existed.

So in a way, we're sitting in magma right now?

Magmatic water carries a lot of the original magma's components,

and as it cools, it creates many kinds of rock.

Even after it changes form, it still holds traces of what it once was.

At this very moment, it's still in the process of turning to stone.

It might be watered down, but hot springs really might be rocks themselves...

By the way, Senpai.

I heard you turned down that offer to work as a museum curator.

Yeah.

There aren't many openings for rock specialists.

Isn't it a waste to pass up?

A waste... yeah, probably...

H-H-Hold on one minute!

Nagi-san! You mean you could have been gone next year?!

Only if I were accepted.

But why would you decline such a great offer?

You could research rocks for a living.

I still have ongoing research projects.

And I'd like to stay in school and continue my research as long as possible.

Stay in school?

Meaning...?

My dream is to be a college professor one day.

That's awesome! I'm sure you can do it, Nagi-san!

Thanks.

Whether it's a college professor or museum curator,

job openings are going to be super hard to come by.

If it's research you want to do, it doesn't have to be at college.

Are you sure it's what you want?

Seto-san, you sound a lot like my professor.

That reminds me, Imari.

You mentioned getting both a museum curator license and a high school teaching license.

What are your plans?

Apparently, there haven't been any openings to

teach earth science in our prefecture lately.

That's a pretty harsh reality.

I'd like to go into research too, but if that's not possible,

I hope I can at least be involved in earth science or mineralogy.

Sorry if this is a bit awkward to hear.

Who knew that even people like Nagi-san and Imari-san have stuff to worry about?

It makes sense when you think about it.

Not a single person in the world has zero worries.

Especially anyone who has an ideal vision for their future.

I keep telling myself that, but I can't help but worry.

No matter how hard it gets, I won't give up on becoming a researcher!

Especially now that I've met you both, I'll work even harder!

Please promise me you'll become researchers.

That way, I can follow in your footsteps!

Follow in our footsteps?

We're not all that.

But we can all try together.