The Castafiore Emerald (1963) is the 21st adventure of Tintin, mostly taking place within the walls of Marlinspike Hall. The protagonists never leave their home in what is considered the most "sedate" tale in the series.
The tale begins with Captain Haddock encountering a camp of Roma setting up in a dump just downwind from Marlinspike Hall. Captain Haddock then generously lets them camp out on his own property, close to his house. This minor event is followed by the news that Bianca Castafiore, Italian opera diva and Abhorrent Admirer to Haddock, has decided to spend her vacation in the Hall. The Captain decides it's time to leave the hall for a vacation of his own. In his haste to leave, Haddock steps on a damaged staircase and sprains his ankle, ensuring that he is not going anywhere.
Castafiore's stay in the Hall turns out to be eventful. One of her prized emeralds goes missing and suspicions fall on the gypsies, while the press misinterprets a random comment of Calculus for an announcement that Bianca is marrying Haddock, resulting in coverage of the events by tabloids and television, along with congratulations from friends around the globe.
- Accidental Misnaming: As usual, Castafiore calls Haddock by a different name every time, which confuses the tabloids trying to romantically link them.
- Angrish: When Captain Haddock receives a phone call from Thompson and Thomson congratulating him over his Tabloid Melodrama-reported engagement to Castafiore, he lets out a series of inarticulate angry syllables before slamming the receiver down.
- Breaking the Fourth Wall: Tintin looks directly at the readers on the album cover and advises them to be quiet.
- Bungling Inventor: Professor Calculus creates a filter that can turn monochrome television signals into colour television, despite Haddock trying to tell him that It's Been Done. It doesn't work very well.
- Chekhov's Gun: Tintin and Captain Haddock spot a magpie in the front yard of Marlinspike very early on in the book. Later in the story, Bianca Castafiore's titular emerald is stolen. It turns out the thief is the magpie.
- Continuity Nod: When talking about her treatment by the media, Bianca Castafiore mentions in passing that the press has linked her romantically to the Marquis de Gorgonzola and to Bordurian secret police chief Colonel Sponsz in the past.
- Crooked Contractor: Criminally Lazy variation. Mr. Bolt takes several weeks to get around to fixing Captain Haddock's broken step, which causes one serious accident and several minor ones. Bolt isn't motivated by financial needs, but by sheer apathy. He can't be too busy because he finds time to join his friends in the drunken marching band, and at one point can be seen reading in the background while his wife claims he is not at home.
- Dream Sequence: Captain Haddock dreams he is listening to an opera singing parrot, while he is seated completely nude in an audience consisting of nothing but fully-dressed parrots.
- The End: The last panel of the story has Bianca's pet parrot, Iago, saying, "Blistering barnacles, that's the end!"
- Fair-Play Whodunnit: The book subverts this trope, as pretty much all the clues pointing towards the identity of the thief turn out to be false, put there just to mislead the reader.
- Famous-Named Foreigner: The pianist Igor Wagner seems to be named after Igor Stravinsky and Richard Wagner.
- Fingore: Downplayed. Haddock's finger is bitten by the parrot and apparently is injured enough to be bandaged, but he doesn't lose the finger and it is well in the end.
- Gag Nose: Temporary; Captain Haddock gets stung in his nose by a wasp, after which his nose swells to big proportions and goes dark red. And to top it off Bianca Castafiore then covers Haddock's swollen red nose with red rose petals, so it looks even more ridiculous.
- Hypocritical Humor:
- "I can't stand animals who talk!" — Snowy.
- "Thief!" — The magpie, who stole the emerald, to Tintin when the latter takes back the emerald.
- Bianca Castafiore comes to Marlinspike Hall to escape the press, but throughout the story is eager to accept various interview opportunities.
- Bianca Castafiore is absolutely horrified and has a fit when a tabloid publishes some pretty random looking picture of her and the parrot, but she doesn't care that the tabloids wrongly published that she and Haddock were going to marry.
- In the same scene, Bianca complains to Haddock that anybody can enter Marlinspike Hall without much trouble, while she invited herself there in the first place.
- I'll Never Tell You What I'm Telling You!: Thompson and Thomson are incapable of keeping their thoughts to themselves.Thomson or Thompson: No, our lips are sealed. We can't tell you whom we suspect, but it isn't anyone in the house. Mum's the word, you know.
Thompson or Thomson: Yes, dumb's the word, that's our motto. So we're not allowed to tell you about the gypsies, though we suspected them from the start...
- Impairment Shot: A very blurry panel depicts the characters' reaction after viewing a very buggy color-television broadcast.
- Mind Your Step: A broken stair in Marlinspike Hall puts Captain Haddock in a wheelchair after he forgets about it. Several other characters trip on the same spot throughout the album. At the end of the story, when Haddock is out of the wheelchair and the stair is freshly repaired, he forgets about it again, steps on the still setting marble, and sends himself flying, undoing the repair in the process.
- No Antagonist: There is no main antagonist—although everyone assumes there is until the end (mainly, suspecting the gypsies).
- Pinball Protagonist: He has his flash of inspiration at the end, but, before that, Tintin spends his time reacting to events and chasing one false lead after another.
- Real Life Writes the Plot: Much of the calamity that happens to Haddock happened to Hergé too. One of his stairs was broken and the repair man always promised he would come by, but it just never happened. Hergé was so irritated by this that he wrote the situation in the story, even gave the repair man the same name: Boullu. A feature about himself in a glossy magazine also bore about the same kind of loose connection to reality as the one in Paris-Flash about Biance Castafiore and the Captain. And the incident with the drunk fanfare band also happened to him in real life.
- Running Gag:
- People (especially Haddock and Nestor) frequently trip over a broken step of the stairs, and Haddock is frantically trying to get the stairs repaired throughout the story.
- Characters are often connected to wrong numbers when using the phone, which leads to them ranting over the phone to someone else than they think they're talking to.
- The parrot talks when Haddock is on the phone, which leads to Haddock cursing the parrot, which is then taken by the person at the other end of the phone line as Haddock swearing at them. This happens a few times.
- "Shaggy Dog" Story: The jewel thief was a magpie. Every single prior clue and lead-in was a Red Herring.
- Shout-Out: Bianca Castafiore mentions in passing that the gossip press has linked her romantically to the Maharajah of Gopal in the past.
- Slice of Life: Herge described the writing of this story as "trying to see if he can maintain tension in a plot where nothing actually happens."
- Tabloid Melodrama: Paris-Flash's cover promises the wedding of Castafiore to Captain Haddock (who can't stand her), and she tells him not to take it too seriously, as she's been linked to hundreds of other men in the past. She later gets upset about the Tempo di Roma's unauthorized expose on "La diva ed il pappagallo" (The diva and the parrot).
- Talking Animal: The parrot talks, sings and shouts, much to the chagrin of Captain Haddock. Snowy even says he can't stand animals who talk.
- Thieving Magpie: Tintin has a Eureka Moment when he hears that Castafiore, still missing her emerald, will be performing in La Gazza Ladra (Thieving Magpie). In said opera by Rossini, the charges of theft against a servant girl are resolved when they discover a magpie was the actual culprit. Sure enough, Tintin finds the emerald in a magpie's nest.