"This is the cheapest diamond."
Translation:Αυτό είναι το φθηνότερο διαμάντι.
In one case, you have something which you are introducing to the discussion ("this") and identifying it as the cheapest diamond.
In the other, you have something which is known to be a diamond, and of all possible diamonds, the one which you want to talk about just now ("this diamond") is the cheapest one.
Would it help to compare it to the following two sentences, spoken while pointing to someone in a photograph?
- This is the Queen of England.
- This queen is the one of England.
The first one might be used to identify a person and say that she is Elizabeth II.
The second one would only make sense if you have already "set the stage" by talking about queens, or if there are several queens on the picture and you want to identify one of them.
So similarly with diamonds, it might make sense in one context to have multiple diamonds and then say which one of them is the cheapest, and in another to simply point out one gemstone and mention that this gemstone happens to be the cheapest diamond.
(That said, there can be contexts where "This is the Queen of England" / "This is the cheapest diamond" can also mean nearly exactly the same as "This queen is the one of England" / "This diamond is the cheapest [one]"; that is, the former sentences can also be used when queens or diamonds are the topic already. The prosody will differ, e.g. "/THIS is the queen of \ENGLAND" versus "/this is the /QUEEN of /ENGLAND", but you can't tell that from the written form.)
Thank you for taking the trouble with all of the above. I imagine a jeweler taking out a tray of diamonds, holding one up and saying - either of the two sentences, both of which would have the same meaning. Greek is very flexible with word order and I think we need a native speaker to contribute to this discussion.
I pictured it as a futuristic lab where a board member asked "What is this?" about an odd, rose-coloured object that had been designed by the corporation, which was now being disolayed, and it was answered as above:
"This is the cheapest diamond. I can withstand pressures of up to three times any other known material, and has a melting point higher than the surface temperature of the Sun. Concentrating over one billion microscopic carbon molecules in every square inch, it durable enough to withstand any form damage, and easy enough to mass produce to sell to every American household within the year. If you'd care to examine your own sample now, gentleman, I think you'd see just how momumental this achievement really is. Think about it: every watch, every knife, every power tool on the continent made more durable than ever before, and at a price that makes silver look like gold in comparison. Yes, gentleman, we truly are at the pinnacle of modern science here. It's a pity you won't live to see it. If you'll excuse me to step into my blastroom, I've something to show you. Its one true flaw: a fatal flaw if you will. You see, because of it was produced using the spatial fields we harnessed from the Tellion Incident, it's inherently unstable. It's only a matter of time until it returns to its original form: and we've found a way to speed up the process. At the touch of a button, we can release a signal to the material that will cause an explosion so powerful that a single ounce can level a city block. Thank you for coming, gentleman. As always, it's been a pleasure doing buisness with you." (detonates crystals, cut scene)
So, you know, little distinctions indicate little nuances. I guess we all just think differently.