Universe Puzzle No. 3

As with last week’s Universe Puzzle, something that cannot be answered by five minutes spent googling, a puzzle that requires you to cudgel your brains a bit, and do some lateral thinking.

Which is the ‘odd one out’? And why?

aragonite, diamond, ice, olivine

This is a puzzle on a “Universal” topic – astronomy and astronomers; space, satellites, missions, and astronauts; planets, moons, telescopes, and so on.

So “ice” is certainly one answer (it’s the only one-syllable word), but not, perhaps, the best answer!

If you think the answer to this puzzle is a cline, rather than a single choice, then try this:

What is the best order to arrange these four in? And why?

Of course, the order they are already in is OK (alphabetical); but is it the best?

aragonite, diamond, ice, olivine

There are no prizes for the first correct answer – there may not even be just one correct answer! – posted as a comment (the judge’s decision – mine! – will be final!), but I do hope that you’ll have lots of fun.

Post your guesses in the comments section, and check back on Wednesday at this same post to find the answer. Good luck!

Update: Answer now posted below

Odd one out: aragonite

This is the only one not yet found beyond the Earth. It’s also the only one which is definitely the result of biological processes (although it can be produced by non-biological ones too).

Cline: there are several good answers, and it is difficult to choose among them.

For example: aragonite, diamond, ice, olivine … found on Earth only, found on Earth and in meteorites only, found/detected in the solar system only, only one detected beyond the solar system.

Check back next week for another Universe Puzzle!

15 Replies to “Universe Puzzle No. 3”

  1. I think this is to do with origins and timescales.

    Diamond, olivine and ice were all around at the beginning of the solar system – diamond from stardust, olivine and ice condensed out of the gas cloud.

    Aragonite is a product of Earth processes.

    So I’d go with Aragonite.

    I’d order them in order of appearance: diamond (primordial), olivine (one of the earliest condensates), ice (a late condensate), aragonite (post-planet formation).

  2. I’m gonna go with ordering according to Mohs hardness, i.e.

    Diamond: 10
    Olivine: 6.5–7
    Aragonite: 3.5-4
    Ice: 1.5

  3. Arargonite is formed from the calcium carbonate from mollusk shells. The others are largely physically generated. Diamond as carbon can form from compressed coal, but usually occurs from nonbiological forms of graphite. So Aragonite is necessarily biological in origin while the others are not.


  4. I’d go with diamond as the odd one out.
    I think aragonite, olivine and ice have hexagonal crystals whereas diamond has octahedral.

  5. Diamond is the odd one out because it’s pure crystalline carbon, which is an element; whereas the other three are compounds.

    Also, diamond has no oxygen atoms; ice (H2O) has one oxygen atom; aragonite (CaCO3) has three oxygen atoms; olivine ((Mg, Fe)2SiO4) has four oxygen atoms.

    Therefore, the best order to arrange those four items are: diamond, ice, aragonite, olivine.

  6. Aragonite. We have enough evidence to believe that, amongst the four listed, the other three naturally form(ed) and exist outside the confines of the Earth.

  7. I was going to be snarky and say “Three of them are rocks, and ice isn’t”, but I suppose that ice could be considered a rock just like any of the others. We just happen to exist in an environment where rivers of molten ice flow like water… so to speak;).

  8. I agree with Navneeth.

    so far Argonite is unique to earth. There is evidence that the other three exist beyond the earth.

  9. Of the four minerals, diamond is the only mineral composed only of atoms from a single element, carbon; the other minerals are composed of molecules.

    They should probably be ordered according to hardness: diamond, olivine, aragonite, ice.

  10. Odd one out:
    Diamond: The rest are hydrated, The only elemental form.
    Aragonite: The only one that can be (but isn’t neccessarily) biologically produced, the only one you wouldn’t expect to occur naturally in a vacuum.
    Ice: The only one that isn’t solid at STP.
    Olivine: The only one that isn’t metastable at STP (Ice melts, Aragonite reverts to calcite, and Diamond reverts to Graphite), The only one that weathers into something else (Ice melts, Aragonite dissolves, and diamonds simply wear down).

    As to order:
    Diamond Olivine Aragonite Ice.
    Diamond, Olivine, Aragonite (decomposes to calcite at 470C), Ice.
    Molecular Weight
    Olivine, Aragonite, Ice, Diamond.
    Specific Gravity
    Diamond, Olivine, Aragonite, Ice.
    So Diamon, Olivine, Aragonite, Ice would appear to be the best order, because it describes the order that the most physical features fall in.

  11. Hmm all of these with the exception of Diamond can be found as a orthorhombic structure. Ice type XI is the orthorhombic form if any care to know. As for order As my wife will always insist Diamond always comes first .The rest Olivine Aragonite and then ice for Hardness.

  12. Here is the order I would put them in for the standards of a pregnant wife:

    1 – Diamonds – Because every woman wants diamonds more than anything whether they are preggo or not.

    2 – Aragonite – forms in mollusk shells and you know how pregnant women’s cravings get! Sometimes they just need their shellfish NOW!!!!

    3 – Ice – Again don’t ever bring a caffeine free soda in a glass to a pregnant wife WITHOUT THE ICE!!!

    4 – Olivine – Most common folk don’t even know what the heck this is, so why would it rank higher than last.

    I hope you enjoyed my 2 cents.

  13. Olivine doesn’t fit – It’s a rock – a mixture of minerals. Diamonds (Carbon), Aragonite (CaCO3), and Ice (H2O) are all pure substances and are therefore minerals.

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