The last page of "The Diamond as Big as the Ritz" is where the theme of youth comes into play. As three survivors – John, Kismine, and Jasmine – sit under the stars and plan their penniless future. Kismine makes a cryptic comment: "I never noticed the stars before. I always thought of them as great big diamonds that belonged to some one. Now they frighten me. They make me feel that it was all a dream, all my youth" (11.27). John makes an even more cryptic reply: "It was a dream […]. "Everybody's youth is a dream, a form of chemical madness" (11.27-28).
This sends us back to the only other passage in the story that explicitly discusses youth. As John is enjoying the opulent luxury of the Washingtons, a strong narrative voice interrupts the tale to comment:
He was enjoying himself as much as he was able. It is youth's felicity as well as its insufficiency that it can never live in the present, but must always be measuring up the day against its own radiantly imagined future—flowers and gold, girls and stars, they are only prefigurations and prophecies of that incomparable, unattainable young dream. (5.3)
This starts us thinking that, while "The Diamond as Big as the Ritz" contains religious allegory and social satire, it is also an allegory of youth. The time John spends at the Washington estate is a sort of dreamy haze – precisely, the narrative seems to argue, like youth itself. It is important that John is a teenager during his time at the château, and that he experiences the flush of first love while he is there. The shiny, gaudy opulence of the Washington estate has a lot to do with the excessive, dreamy way we live youth – or so Fitzgerald argues.
As John and Kismine are escaping from the château, he tells her that "it's impossible to be both [free and poor] together," adding that he "should choose to be free as preferable of the two" (9.29). By this reasoning, he tells Kismine to take a pocketful of diamonds with them as they leave. The idea is that, if they have the diamonds, they will be rich, and this will allow them to be free.
Except it turns out that Kismine, clearly not fated to be a jeweler, took rhinestones instead. So what does this mean in terms of John's plan? One interpretation is that, since they are now poor, they are necessarily not free. Another is that John was wrong in his assertion and the ending proves it – they escaped from the château and are free, despite being poor. Yet another possibility is that the ending forces us to reinterpret the ideas of "freedom" and of "wealth." John has his life and a woman who is ready to be his wife; in this sense, he is "rich." You could also argue that John, despite having escaped from the Washingtons is still captive to his own preoccupation with wealth. The ending leaves it up to you to interpret John's earlier claim on freedom and poverty.
In "Symbols, Imagery, Allegory," we discus the fact that John is from Hades, which in Greek mythology was another name for Hell. We also take a look at the Washington estate as representing a sort of Garden of Eden-like paradise. At the end of the story, then, we see that John, Kismine, and Jasmine have escaped from Eden, in order to go live in Hell.
That might sound a little backwards. One possibility is that Fitzgerald's characterization of these to locales is ironic; the point being that the Washington estate, which seems like Eden, is really its own form of Hell. (After all, prisoners are held there, no one can escape, and God turns his back as it is attacked.) Hades, on the other hand, can be a sort of Heaven in itself, because it is free of the evils which plague the Washingtons. Another possibility is that Hades really is like Hell, which is a sad (but not unhumorous) conclusion to the story.
The humor comes in when you consider the attitudes of our three remaining survivors as they look forward to their future in Hell. Kismine is excited at the prospect of being poor; John isn't even upset about the fact that she left her diamonds behind; and Jasmine's attitudes is best described as a sort of contented acceptance. "Oh well," they seem to say, "now we're going to be poor for the rest of our lives. No big deal; let's take a nap."
Because of this general attitude, and because of the religious allegory pervading the ending, we can't help but think of Candide, a satire written by Voltaire in 1759. In Candide, the story's protagonist and friends undergo a series of awful events – torture, natural disaster, rape, etc. – and yet come out at the end with an oddly optimistic attitude. Voltaire's point was to criticize the philosophy of Optimism, which he did by satirizing its followers. At the end of Candide, the various protagonists, crippled and deformed by their various misfortunes, set to work in a garden for the rest of their days. Their attitude is, just like the attitude of John, Kismine, and Jasmine, a sort of contented acceptance. "Oh well," they seem to say, "let's tend to our garden."
There are several ways in which "The Diamond as Big as the Ritz" may allude to Candide in this final scene. First of all, the characters share the same absurd reaction to misfortune while contentedly anticipating a rather bleak future. You've also got the religious allegory to consider. The garden at the end of Candide certainly refers to the Garden of Eden, which means the characters have arrived at an ironic rendering of an Eden-like paradise. The characters in "The Diamond as Big as the Ritz," on the contrary, have left Eden and instead gone on to Hades, or Hell. It's an ironic twist on what is already an ironic satire – clever stuff, but nothing short of what we expect from Fitzgerald.