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GeneralFun with riddles

29th Nov 2019 15:15 UTCcascaillou

Mineralogical riddles, of course:

1) Some disorienting news

As two letters literally turned our whole world upside down, we both stood petrified, staring at each other with gravity. Who are we?

2) Paradox

I am a mineral but I'm not quite myself. I have strong bones and I'm well hydrated, but if it gets too hot I'll sweat and breath out the same air than a man. By the way, Étienne Lantier is a good friend of mine.

Which mineral am I?

3) Into darkness

I am as dark as the night,
from the depth of which
the lady in blue reminds me
of a god that binds us both.

Which mineral am I?

4) The eternity stone

As dust, the quicker I run the nearer the end is.
As a crystal, I keep the future into a cycle.

Which mineral am I?

5) Thunderstorm

I vanish in the rain, and yet I brought the thunder with me from the east.

Which mineral am I?

6) The missing link


What's the missing letter?

7) S
ibling rivalry

Each of my six brothers has his own room, but I'm the only one who doesn't have any mirror in his room.  What does my room look like?

8) An impossible duo

Name two natural minerals made up of aluminium and oxygen and phosphorus (all and only these).

[all first seven riddles have been solved by now, answers below]












































2nd Dec 2019 14:33 UTCcascaillou


1) Stalactite and stalagmite

Clues: exchanging 'ct' and 'gm' will turn one into another (literally turning them upside-down), they are a pair of petrified concretions facing one another and linked by gravity (water dripping from one to the other).

2) Whewellite (or weddellite)

Clues: That was  mostly a chemistry oriented riddle.  An organic mineral ("not quite mineral"). Contains calcium ("strong bones"), hydrated, evolves H2O ("sweat") and CO2 ("same air than a man") when heated, thus obviously containing carbon (moreover, such thermal decomposition products are also typical for organic substances). Occurs in coal deposits (a quick internet search shows that "Etienne Lantier" is a coal miner in the famous novel Germinal by Emile Zola). 
Indeed, whewellite is Ca(C2O4)·H2O (an hydrated calcium oxalate, in the class of organic minerals, and occuring in coal deposits).

3) Neptunite

Clues: the key to the riddle was to find out who was that "lady in blue in the depth of the night" which was a reference to the blue planet neptune, then the god is obviously Neptune (roman god of the sea), both the (dark) mineral and the planet being bound by his name (both named after him).

4) Quartz

Clues: quartz keeping a measure of time as sand running inside an hourglass, or as a crystal in a quartz watch (thanks to its piezoelectric properties).

5) Niter

Clues: Niter (potassium nitrate) being water soluble ("vanish in the rain"), and an essential component of gunpowder which was first invented in China ("thunder from the east").

6) T

Clues: mohs hardness scale in reverse order (initial letters), T standing for Talc.

7) Triclinic

Clues: the seven crystal systems (seven "brothers" in total), no mirror plane in the triclinic lattice ("triclinic room").

8) Riddle hasn't been solved yet

2nd Dec 2019 14:41 UTCEd Clopton Expert

#6 is T.  Still working on the others.

2nd Dec 2019 15:12 UTCcascaillou

Well done, answer to the sixth riddle is indeed T

2nd Dec 2019 16:25 UTCErik Vercammen Expert

7: the triclinic cristal sistem

2nd Dec 2019 16:26 UTCErik Vercammen Expert

5 is ice, espcially as hail

2nd Dec 2019 16:43 UTCcascaillou

Answer to number 7 is indeed triclinic, congratulations!

Ice would indeed make a clever answer for the fifth riddle, but I was actually thinking of another mineral.

2nd Dec 2019 17:43 UTCcascaillou

I've reformulated the fifth riddle, it's now less equivocal.

2nd Dec 2019 18:24 UTCFrank K. Mazdab Manager

I'm going to guess nitre for #5, because thunder from the east suggests gunpowder made first in China, and of course it's water soluble.

2nd Dec 2019 18:35 UTCFrank K. Mazdab Manager

Alas, my gyroid avatar shares #7's mirrorless lament.

2nd Dec 2019 18:36 UTCcascaillou

Indeed, the answer to the fifth riddle was Niter :-)

2nd Dec 2019 20:11 UTCKeith Compton Manager

Riddle 1 is Tin  (Sn)

2nd Dec 2019 20:28 UTCcascaillou

Nope, answer to the first riddle is not tin. Hint: note that the question is "who are we?"

3rd Dec 2019 06:25 UTCD Mike Reinke

I want to guess #3 is neptuneite, being connected to water, blue benitoite, and that meaning 'blessed', but that's just a guess. I'm not sure those are what you are referencing.

3rd Dec 2019 09:06 UTCcascaillou

Yes, answer to the third riddle is neptunite! 

I (neptunite) am as dark as the night (indeed appears almost black),
from the depth of which (night)
the lady in blue (the blue planet Neptune) reminds me
of a god (Neptune, the Roman god of the sea) that binds us both (by his name, since both the planet and the mineral were of course named after him)

The key to the riddle was essentially to guess who was that "lady in blue in the depth of the night", then it was pretty straightforward. 

3rd Dec 2019 12:43 UTCMatt Courville

Like Keith I had been thinking of the periodic table of elements for #1

S - sulfur with the rise of the industrial age
U - with the rise of the nuclear age
C - with the modern age of the carbon footprint

Sure there are 3 but at least I gave it a go ;)

3rd Dec 2019 13:11 UTCcascaillou

Nope :-)

3rd Dec 2019 14:04 UTCFrank K. Mazdab Manager

perhaps H and O, the two components of water, where life developed below the surface?

3rd Dec 2019 14:30 UTCcascaillou

Nothing to do with elements, actually. 

3rd Dec 2019 14:47 UTCcascaillou

I've reformulated the first riddle with additional clues so to make it easier.

3rd Dec 2019 14:53 UTCKevin Conroy Expert

Are the letters "un"?

3rd Dec 2019 14:55 UTCcascaillou


Make sure to read the new version of the riddle, I've added new clues.

3rd Dec 2019 15:30 UTCMark Holtkamp

Perhaps he letters for #1 are "KT" ?

3rd Dec 2019 15:38 UTCcascaillou

In english, it's not written with a K but I think you got it, does it also work with M and G ? 

3rd Dec 2019 15:54 UTCMark Holtkamp

Hmmm in that case I think I got it wrong, I was thinking of the K-T Boundary, aka 
the Cretaceous–Paleogene boundary :-) 

3rd Dec 2019 16:02 UTCcascaillou

Sorry, but the answer is not related to the K-T boundary (that was clever, though). 

Then I guess the riddle is still ongoing.

Don't overthink it, this riddle doesn't require extensive knowledge of mineralogy/geology.

3rd Dec 2019 17:51 UTCErik Vercammen Expert

The Earth and the Moon?

3rd Dec 2019 18:11 UTCEd Clopton Expert

2:  Coal?  Coal is neither animal nor vegetable, so by elimination it could be called a mineral; it contains some moisture; when heated the moisture steams off, and the carbon oxidizes to CO2, the same gas a person exhales as a result of metabolism.  And Etienne Lantier (as I just learned) was a coal miner in a novel by Emile Zola.

3rd Dec 2019 18:16 UTCcascaillou

No astronomy involved here.  The answer is definitely mineralogy/geology related.

The trick with the letters might not become obvious until you get an idea of what the riddle might be about, but anyway all the wording was entirely thought to illustrate what the riddle is about, so maybe don't focus on the letters thing, but rather on the whole description.

3rd Dec 2019 18:23 UTCEd Clopton Expert

1:  After maddeningly brief consideration, my wife (the non-mineralogist) suggests "stalactite" and "stalagmite"; exchanging the ct and the gm between the two words makes the two formations change places (i.e., turning their relationship upside-down).  The two are separate but linked by gravity, which causes water to drip from one to the other.

3rd Dec 2019 18:26 UTCcascaillou

Women remain our masterminds :-)

Answer to the first riddle: stalactite and stalagmite that is!

3rd Dec 2019 19:21 UTCKevin Conroy Expert

My wife is definitely the smart one!

My "un" guess was for "unearthed", which I now know was REALLY wrong.

3rd Dec 2019 18:47 UTCcascaillou

Ed Clopton Expert  ✉️

2:  Coal?  Coal is neither animal nor vegetable, so by elimination it could be called a mineral; it contains some moisture; when heated the moisture steams off, and the carbon oxidizes to CO2, the same gas a person exhales as a result of metabolism.  And Etienne Lantier (as I just learned) was a coal miner in a novel by Emile Zola.
The answer is not coal. Coal is rather regarded as a rock.
But the mention of Etienne Lantier was indeed meant to suggest coal (there's a reason for that). And "breathing out the same air than a man" was indeed a reference to CO2 being evolved with heating, as well as moisture.

There are several clues to be deciphered in this riddle, but I guess the answer is now within close reach.

3rd Dec 2019 19:06 UTCBret Howard

For #2; what crossed my mind was a zeolite.  They can easily release water and CO2 as well as readsorb them.  Have a nice well defined, open but rigid structure - "bones".  And the link to coal could be catalysis.  Just my wild guess.....

3rd Dec 2019 19:26 UTCcascaillou

It's not a zeolite. Actually, it's not a matter of rigidity of the mineral's structure.

3rd Dec 2019 19:12 UTCFrank K. Mazdab Manager

perhaps at this point we should be asking if it's a European sparrow or an African sparrow?

3rd Dec 2019 19:24 UTCcascaillou

riddles are an utterly serious matter, leave the sparrows aside :-))

Nevertheless, I just checked, and it seems it has not been reported from Africa. So definitely more of an european sparrow than an african one.

3rd Dec 2019 20:11 UTCEd Clopton Expert

"but I'm not quite myself."  Is pseudomorphism or fossilization involved?

3rd Dec 2019 20:26 UTCcascaillou

No. But the concept behind "a mineral not being quite himself" is indeed meaningful (although some of the clues that were already deciphered previously might already point you in the same direction). Another important clue is hidden behind the statement "I have strong bones". Then you'll have all the necessary data to find out which mineral the riddle is about.

4th Dec 2019 03:02 UTCKeith Compton Manager


4th Dec 2019 03:51 UTCFrank K. Mazdab Manager

A carbon dioxide clathrate would fit several of the criteria:

1) It has "strong bones" (the ice cage that holds the CO2).
2) It is well hydrated (it's fundamentally made of H2O)
3) It gives off its CO2 when heated.

It occurs as snow on Mars (and potentially on Earth, in the polar regions?), so whether it's a mineral or not I suppose will have to await the IMA taking a break from re-naming amphiboles and deciding if inorganic extra-terrestrial solids that aren't stable at Earth ambient P-T conditions should be minerals... :-)

I don't think I can come up with any connection to Etienne Lantier, since before reading Ed's post I did not know who that was.

Another thought is whewellite or weddelite.  They are minerals but not quite minerals (as partially organic, they border on the definition, so perhaps not quite themselves). They are well-hydrated, and as oxalates they would evolved CO2 when heated.  They occur in coal seams, so Etienne Lantier may have run across them during his work. But no inkling how "strong bones" would fit, however.

4th Dec 2019 04:09 UTCD Mike Reinke

#3 is T for talc? The letters are the most scale, but in reverse order?
Looking through some mineral lists for inspiration, I thought "maaaybe"....

4th Dec 2019 09:29 UTCcascaillou

it's actually the sixth riddle, yes T is for Talc

4th Dec 2019 04:56 UTCD Mike Reinke

Frank I love your Monty Python reference. Since there is calcium in whewillite and that's in Bones would that not suffice?
  I thought #2 MAY have to do with alcohol? But the strong bones has me stumped totally in that direction. Alcohol metabolism doesn't have much to do with having strong bones, last time I checked.

4th Dec 2019 06:30 UTCD Mike Reinke

4a doesn't sound grammatically correct. I'm guessing something like iron as in iron in a meteorite that was an asteroid before it was a meteorite but I have no idea what the divided part would represent

4th Dec 2019 10:08 UTCcascaillou

I've reformulated the fourth riddle is a more intelligible way.

4th Dec 2019 10:37 UTCFrank K. Mazdab Manager

Is #4 quartz?

the piezoelectric nature of the crystal lets watches keep time.
its weathering carries the fragments of long-ago crystallized rocks down from the mountains to the sea.

4th Dec 2019 10:50 UTCcascaillou

Answer to the fourth riddle is indeed quartz.

Quartz being the "keeper" of time, as a single crystal in a quartz watch (thanks to its piezoelectric properties), or as sand running (falling down) inside an hourglass. The hourglass clue was hard to guess, but the watch clue was already more than enough to think of quartz.

4th Dec 2019 09:46 UTCcascaillou

And we have a winner! Congratulations Frank, answer to the second riddle was indeed whewellite, and I would have also accepted weddellite...but since you mentioned both I guess that's an A!

That riddle was mostly about the chemistry of the mineral:

"I am a mineral but I'm not quite myself": quite literally "a mineral that is not quite...mineral", that's an organic mineral!

"I have strong bones and I'm well hydrated": that was to suggest presence of calcium (strong bones), and an hydrated mineral

"if it gets too hot I'll sweat and breath out the same air than a man": that suggested that heating (to decomposition) would release H2O and CO2. Such decomposition products could also make you think of an organic compound, but most importantly that was telling you that the mineral contained carbon and water.

So at this point you knew that the mineral contained calcium, carbon, hydrogen and oxygen. And you might also have guessed that it was likely an organic substance.

"Étienne Lantier is a good friend of mine": a quick internet search was required to find out that this fictional character was a coal miner (from what's probably Zola's most famous work). This was the only clue that wasn't related to chemistry but rather to gitology/paragenesis of the mineral, since it does indeed occurs along with coal, in coal mines.

Whewellite being an organic mineral, an hydrated calcium oxalate, with formula Ca(C2O4)·H2O, that can be found in some coal deposits.

4th Dec 2019 10:06 UTCFrank K. Mazdab Manager

I suppose "I am a mineral but not quite myself, but of course you'll still find me in stones" would be too on the cuff?

4th Dec 2019 10:32 UTCcascaillou

That was also the point of suggesting its presence in coal mines

4th Dec 2019 11:19 UTCcascaillou

Well congratulation to all participants (and their wives!) for solving all those riddles. 
I hope you enjoyed the game (I definitely had some fun in creating those).

6th Dec 2019 16:04 UTCcascaillou

I've been adding one more riddle (number 8). It should be solved relatively easily I guess.
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