An entry in Fortnightly Topic Challenge #39: Deep Down in the Dungeon 1.
You enter a well-lit, round chamber. As the party enters the room, the door behind you slams shut. No amount of effort can seem to budge it.
Choosing to investigate the room, you first notice a set of scales set on a short, round column in the center of the circular room.
Coming closer, you see six gemstones lying next to the scales: an emerald, a ruby, a diamond, a sapphire, an opal, and a topaz.
Inscribed on the pedestal is this verse:
Six stones of great worth lie before you
Awaiting a place of their own
Six shelves line the wall around you
Waiting to hold their true stone
The scales in the center will guide you
But not size nor mass will they teach
Instead they are magically gifted
To measure the rightness of each
One method of placing will save you
All others will doom you to die
But here is one hint to assist you
You entered from envious eye
Looking around, you notice that there are indeed six small shelves set in to the walls at regular intervals. One of these is carved in to the door through which you entered.
The cleric proposes ordering the gems by what they represent.
The druid proposes ordering the gems by colour.
The mage proposes ordering the gems by their name (noting that their initials spell ‘SORTED’).
The thief proposes ordering the gems by relative value.
While they argue over the best strategy, and the best pairs of measurements to try, the fighter goes ahead and tries a few measurements.
He first weighs the emerald and the ruby, and the side with the ruby goes down.
Second, he weighs the emerald and the topaz, and the scales balance.
Third, he weighs the sapphire and the opal, and the opal side goes down.
Fourth, he weighs the emerald and the diamond, and the side with the emerald does down.
“Aha!” he exclaims. “Now we’re getting somewhere!” He carefully considers the results. “The ruby is heavier than the emerald,” he reasons. “And the emerald is heavier than the diamond. So, the ruby must be heavier than the diamond.”
To test his theory, he weighs the ruby and the diamond, and the diamond side goes down.
“Cursed sorcery!” he exclaims, and before anyone realizes what is going on, he has revealed his berserker tendencies and smashed the scales to pieces.
The rest of the party is horrified, disappointed, and about ready to call it a night, until the hireling (played by the mage’s little sister), who has been carefully listening and taking notes, informs them: “It’s easy, really.”
She then proceeds to take the gems and – one by one – places them correctly, in a manner none of the others had considered, thus securing her new role as party leader.
How did she do it?