Lovely young Rachel Verinder receives an unexpected and (to her mother) unwelcome 18th birthday present from her late uncle, the family Black Sheep. Mr. Murthwaite, a famous explorer and one of the party guests, tells Rachel and Mrs. Verinder that the large yellow diamond was stolen from a Hindu idol 20 or 30 years before and that the Indian 'jugglers' who entertain the party are nothing of the kind but, most probably, Hindu priests trying to regain their sacred stone. That very night, the diamond disappears.
Rachel has two suitors, both her first cousins, Godfrey Ablewhite and Franklin Blake, staying in the house. It soon becomes clear that she suspects Blake of being the thief. The detective called in on the case, Sergeant Cuff, on the other hand, suspects Rachel herself, along with one of the maids, who has a criminal background. The true solution proves to be much more complex than either theory, involving several parties, all with their own unconnected motives.
The novel is noteworthy not only for codifying, if not originating, many Detective Fiction tropes, but for being a compelling work of social critique and examination. The narrators include the butler to an aristocratic house, a penniless spinster with a Vocation, and a doctor who is explicitly of mixed race. These are all characters on the fringe of Society, yet Collins gives them voices and important roles in observing and reporting the story's action. He also touches deftly on themes of imperialism and colonialism, as well as medicine and drug addiction.
This story provides examples of:
- A Day in Her Apron: Subverted. One of Betteredge's anecdotes about his wife is about a time when she refused to cook his dinner — so he did it himself, and (by his own account) cooked it without difficulty and left the kitchen spotless.
- All Love Is Unrequited: Poor Rosanna Spearman. Drusilla Clack, it is implied, might be in love with Godfrey Ablewhite — she sure talks about the "religious fervor" he inspires in her in very passionate ways.
- And Another Thing...: One of the Indians visits the offices of a couple barristers merely to form an excuse to ask one final question before leaving.
- Awful Wedded Life: Betteredge has nothing good to say about his deceased wife and expresses his gratitude that Penelope is nothing like her.
- Babies Ever After
- Beauty Equals Goodness: Not intentionally but various characters seem to display a subconscious prejudice towards those considered unattractive. Franklin Blake is dismissive of 'ugly' Rosanna and oblivious to her clear affections for him, though Sergeant Cuff points out that he would have found out fast enough if she had been better-looking. However he gets on very well with Ezra Jennings, whose piebald hair and 'gipsy complexion' turns many people off him, while Mr. Bruff and Betteredge are openly dismissive and sceptical of his involvement in the investigation, until it is proven correct. Truth in Television
in that the book was published during the Victorian Era.Sergeant Cuff: The ugly women have a bad time of it in this world; let's hope it will be made up to them in another. - Bewildering Punishment: Franklin has no idea why Rachel is suddenly so angry and cold towards him. Not until she tells him that she "saw him take the Moonstone with her own eyes."
- Black Sheep: General Herncastle, Rachel's wicked uncle. He committed many crimes in India as a soldier, and for that and other reasons he is persona non grata to the rest of the family. His gift to Rachel is so unexpected it's immediately suspicious.
- Broken Bird: Rosanna Spearman of course, but also the unlikeable Miss Clack.
- Book Ends: The prologue and epilogue are set in India.
- Call to Agriculture: Sergeant Cuff retires to cultivate roses.
- Chekhov's Gunman: Dr Candy and Ezra Jennings.
- Crime Reconstruction: Used to figure out what happened to the Moonstone.
- Cringe Comedy:
- Drusilla Clack's chapter, which consists largely of her attempts to self-righteously proselytize at the most awkward and inappropriate times possible.
- Rachel's birthday dinner, during which everyone seems somehow incapable of making decent conversation, and whoever does try to make conversation manages to spectacularly put their foot in their mouth.
- Driven to Suicide: Rosanna at the Shivering Sands.
- Enlightened Antagonist: The Hindu Brahmin priests, who seemingly possess some sort of supernatural powers, and who are perceived by the main characters as antagonistic because they intend to steal the stone and return it to India where it actually belongs.
- Explosive Results: Discussed for laughs. Rachel's guardian Mrs Merridew is convinced that any scientific experiment will inevitably end in an explosion. Becomes a Brick Joke when Rachel needs to get her out of the way in a hurry, and achieves this by telling her the explosion's imminent.
- Famed In-Story: Sergeant Cuff, who is known for discreetly solving various embarrassing conundrums the wealthy are faced with.
- Genki Girl: Godfrey's sisters, whom Betteredge calls 'the Bouncers'.Everything the Miss Ablewhites said began with a large O; everything they did was done with a bang; and they giggled and screamed, in season and out of season, on the smallest provocation.
- Great Detective: Sergeant Cuff, who is looking forward to a long retirement where he can devote himself to his roses.
- Hidden Villain: Godfrey, who seemed the most trustworthy, pious, and charitable of all (at least, he fooled the various narrators).
- Holier Than Thou: Miss Clack.
- Hopeless Suitor: Rosanna Spearman, being an ugly servant girl, for the wealthy socialite Franklin Blake. He doesn't even have a clue that she might be in love with him, and Betteredge bursts out laughing when first told about all that, because it's so ridiculous for Rosanna to be in love with an upper-class man.
- How Did You Get It?: The Moonstone is pawned to a moneylender. His first question is "How did you come by this?" and he refuses to lend anything until he's got a truthful answer.
- In Touch with His Feminine Side: Mr. Ezra Jennings says to Franklin Blake, "Some men are born with female constitutions... and I am one of them!" (He's crying Tender Tears at the moment, and is shown to be emotional and gentle to his patients).
- Kid Detective: Introduced in the last couple of chapters, "Gooseberry," a boy with large and prominent eyes, whom Cuff hires to track down a suspect. Cuff speaks very warmly of the boy's innate detective smarts.
- Kissing Cousins: Rachel seems unaware that there are eligible young men in England who are not related to her. The only suitors she considers in the entire book are her two first cousins.
- Lazy Bum: Mrs Ablewhite.My Aunt Ablewhite is a large, silent, fair-complexioned woman, with one noteworthy point in her character. From the hour of her birth she has never been known to do anything for herself. She has gone through life accepting everybody's help, and adopting everybody's opinions.
- Lemony Narrator: Gabriel Betteridge
- Living a Double Life: Godfrey Ablewhite, who seems to be a generous and courteous philanthropist, has actually been siphoning off money trusted to him for his ward's care, and keeps a mistress in the country.
- Love at First Sight: Rosanna Spearman for Franklin Blake.
- Leave the Two Lovebirds Alone: After proving Franklin Blake's innocence, Ezra Jennings sees Rachel waiting beside him as he begins to wake and leaves the room to let them be alone together.
- Maybe Magic, Maybe Mundane: The way the Indians unerringly track the Moonstone, at one point appearing to divine its location using a drop of ink in the palm of a hypnotised boy, although Mr. Murthwaite dismisses this as just for show.
- Meaningful Name: The moneylender called Luker — a phonetic spelling of 'lucre'.
- Measuring the Marigolds: Gabriel Betteredge speaks out against gentlefolk who take up a "natural science" hobby in order to dissect flowers. He asks, "Is its perfume any better, or its color any prettier, when you do know?" But what he chiefly objects to isn't the science, but the callous and destructive way that gentlefolk pursue the hobby out of sheer boredom.
- Mineral MacGuffin: The Moonstone itself, a large yellow diamond. The diamond would be more valuable if cut up into six or seven smaller stones, so General Herncastle keeps that option on hand—which also keeps the Indian priests at a distance, because they want the stone to remain whole.
- No Celebrities Were Harmed: Explorer Mr. Murthwaite is clearly based on the adventurer Richard Burton.
- Non-Indicative Name: The title, insofar as it refers to a yellow diamond, and not the actual gem
known as a moonstone. Nor is it a stone that comes from the moon, awesome as that would be; it's only sacred to (and stolen from an idol of) some Indian Moon god. - Old Retainer: Gabriel Betteredge, who refers to his lady and Miss Verinder in the warmest of terms — far more warmly, in fact, than he refers to his wife.
- Precision F-Strike: From the senior Ablewhite: "Miss Jane Ann Stamper be ——!"
- Quicksand Sucks: The Shivering Sand. Dangerous, but not an impossible trap. It's used by a certain character to hide an incriminating piece of evidence, using a locked box and a chain, and to commit suicide. Actually a more realistic take on the trope, as the Shivering Sand is closer to a tidal mudflat, which is very dangerous and acts a bit more like quicksand-in-tropeland than quicksand in reality does.
- Red Herring: Innumerable! Rosanna Spearman is a noteworthy one, an ex-thief who now works in the Verinder house, and who acts awfully suspicious around Franklin Blake. Because she's head-over-heels for him. Rachel's peculiar behaviour also arouses some suspicion that she knows more than she's letting on. Indeed she does but that is because she believes it was Franklin who stole the diamond.
- Red Right Hand: Rosanna Spearman, ex-thief and maid, is a hunchback. Ezra Jennings, who has a dark secret in his past, has "piebald" hair (dark with white streaks, also quite curly). Neither are bad people, and the true villain is handsome and healthy.
- Ripped from the Headlines:
- Herncastle acquired the Moonstone, under circumstances implied to be suspicious and shameful, while looting Seringapatam after the siege of 1799. Collins may well have been thinking of the (at the time of the book's writing) much more recent looting of other Indian artefacts by British soldiers during the Indian Mutiny.
- Betteredge has several discussions with other characters about whether more democracy is a good thing or not, which probably reflects the serial being written around the time of the passage of the Second Great Reform Act (1867) which expanded the voting franchise in the UK.
- Several aspects of the mystery, including the importance of a stained nightgown and suspicion falling on the teenaged daughter of the household, bear a resemblance to the Road Hill House murder in 1860. Sergeant Cuff also has similarities to both Detective Inspector Jack Whicher, who investigated that case, and his boss Dolly Williamson (whose love of gardening was the inspiration for Cuff's interest in roses).
- Running Gag:
- Betteredge's firm conviction that the answers to all of life's problems can be found within the pages of Robinson Crusoe, and him consulting it as though it were the Bible.
- Sergeant Cuff's obsession with roses, and in particular his never-ending Serious Business argument with the Verinders' gardener about the best way to grow white musk roses.
- Scrapbook Story
- Shipper on Deck: A Shipping War In-Universe, no less! Early in the book, Betteredge and his daughter, Penelope, butt heads over whether Rachel covets Godfrey Ablewhite's affections (Betteredge's view) or Franklin Blake (Penelope's).
- Shout-Out: Betteridge believes that Robinson Crusoe contains all of the world's wisdom.
- Spirited Young Lady: Rachel, maybe even a Tsundere.
- The Stakeout: Probably the earliest example.
- Stealth Insult: Sergeant Cuff says to Gabriel Betteredge that he fancies himself to be tender-hearted towards the physically disabled (i.e. Rosanna Spearman)... and then, seeing that as Betteredge is being a little slow on the uptake, Cuff adds that he feels rather tender-hearted towards Betteredge.
- Switching P.O.V.: The Framing Device is Frankiln Blake gathering witness accounts on the entire affair for future perusal of his and Rachel's descendants.
- Taking the Heat: The two main suspects (both female) turn out to have been independently covering for the same man, whom they both love, after seeing what each believes to be proof that he stole the eponymous gemstone.
- Treasure Is Bigger in Fiction: The Moonstone itself is a big ol' hunk of polished diamond, maybe the size of a fist. However, a bit of realism for the gemstone— big as the stone is, it has a flaw at its heart which reduces its value. If a skilled jeweler cut it into smaller stones, they could reap a real profit.
- True Art Is Ancient: Mocked, In-Universe, by Ezra Jennings:"All classical works; all (of course) immeasurably superior to anything produced in later times; and all (from my present point of view) possessing the one great merit of enchaining nobody's interest, and exciting nobody's brain."
- Twist Ending: Another very early example.
- Type Caste: Collins correctly states that observant Hindus (such as the three priests, who are specified to be Brahmins) lose their caste when they cross the sea/large body of water.
- Unbuilt Trope:
- General Herncastle's Genre Savvy way of protecting himself from the three Indians over the years by legally engineering matters so the Moonstone will be broken up by jewellers if he is killed, in stark contrast to how many later stories would treat this sort of thing as an inevitable curse.
- Sergeant Cuff feels like a deconstruction of the Great Detective trope as he is Famed In-Story but, though doing much better than any other investigator for most of the story, fails to solve the mystery alone. However, he is arguably the first example of a Famed In-Story Great Detective in English literature!
- Ur-Example: Famously described by T. S. Eliot as "the first and greatest of English detective novels".
- Wham Episode: The chapter containing the revelations from Rachel and (posthumously) Rosanna regarding the thief's identity.
- Women Are Wiser: In regards to love, Penelope is the first to realize Rosanna's feelings for Franklin Blake. She's also correct that Rachel loves Franklin Blake instead of Godfrey Abelwhite.
- Year X: An interesting aversion compared to many contemporary works, instead giving exact dates for the story in the years 1848 and 1849 (about twenty years before it was written). Oddly, it never mentions the European revolutions of 1848 despite Drusilla Clack going to live in France and Franklin Blake also travelling through Europe at the time.
Tropes found in the 1996 BBC adaptation:
- Composite Character: Mr Murthwaite is written out; his lines are given to Doctor Candy. Similarly, Nancy is removed and Penelope gets her lines.
- Compressed Adaptation: The story jumps from Lady Verinder's death to Mr Blake senior's death, omitting the subplot where Rachel and Godfrey get engaged and then decide against marrying.
Tropes found in the 2016 BBC adaptation:
- Adaptational Angst Upgrade: Unlike in the book, Rachel and Franklin aren't immediately reconciled by Ezra Jennings's experiment, and continue to suspect each other until the truth finally comes out.
- Comforting Comforter: Rachel to Franklin, when he falls asleep at the end of Ezra Jennings's experiment.
- Death by Adaptation: Doctor Candy dies rather than just losing his memory.
- In Medias Res: The adaptation begins with the start of Franklin Blake's Third Narrative, then flashes back to the beginning once he meets Betteredge in Yorkshire.
- Narrator All Along: Each episode opens with the backstory of the diamond, told as a puppet show. At the end of the last episode, it's revealed that the show was being presented by Franklin and Rachel's Babies Ever After.
- Race Lift: Betteredge is West Indian, and Penelope is accordingly mixed-race.
- Sexy Shirt Switch: It's hinted at in the book, but this adaptation makes it quite clear that Rosanna is turned on when she has to conceal Franklin's nightgown by wearing it under her clothes.
- Shirtless Scene: Franklin Blake and Godfrey Ablewhite each get one, with Rachel and Miss Clack, respectively, Eating the Eye Candy.
- Spared by the Adaptation: Ezra Jennings.
- Vomit Indiscretion Shot: Penelope's reaction to the paint fumes is shown onscreen.
