The Moonstone from Wilkie Collins’ novel of the same name; supposedly stolen from an idol (possibly the first appearance of that trope in fiction)
The Stone from the Eye of the Idol in the 1924 and 1940 versions of The Thief of Bagdad. In each case, it acts like a far-seeing crystal ball. (In the original story it’s a magic telescope!)
That magic ring from Bram Stoker’s Jewel of Seven Stars
The Dracula ring created th movie House of Frankenstein (1944), later worn by Bela Lugosi (who didn’t play Dracula in that film) and was eventually given to Forrest J. Ackerman, who showed pictures of it in Famous Monsters of Filmland. He was wearing it when I shook hands with him at the 1989 50th anniversary World Science Fiction Convention. It sold at auction in 2009 for $46,000. I don’t know who has it now.
And from the same series, and the same wearer, there’s a miniature globe of the planet Barrayar, hanging by countergrav from a pendant and spinning and displaying changing weather patterns. A couple of other characters have earrings made from a pair of such globes (from two different planets that they have ties to).
On Beta Colony, another world in the same setting, different styles of earrings are used to signal a wide variety of orientation and relationship status.
Before the rings, they had belts. Very plain-looking (sort of like a watchband, with vertical segments). From what I see online it was 1965 when the changeover to rings happened.
Upthread there’s a short debate on whether or not belts count as jewelry. At least the Superheroes were not using the belts to hold up their pants!
The Time Lord known as The Master was reincarnated after having been cremated, thanks to the signet ring he was wearing (covered in Gallifreyan script), and a ritual performed by the Disciples of Saxon.
Almost certainly based on Dracula’s reconstitution in various Hammer movies.
Do pocket watches count as jewelry? Because both the Doctor and the Master used ornate watches to hide their alien nature and store their temporarily erased memories.
Looking back through, it’s mostly rings, with neckwear and bracelets making a good showing; a handful of earrings, and the odd torc, crown, pocket watch, brooch/pin etc.
Thinking of other adornments:
Sansa’s bejewelled hairnet in Game of Thrones
Vincent’s drug-dealer’s wife’s tongue piercing in Pulp Fiction
…?
The Amber novels have the Jewel of Judgement, a red orb on a necklace that among other things can call lightning, be used to inscribe a new Pattern, and seems to be the stolen Eye of the Serpent of Chaos.
Elizabeth Moon’s Paladin’s Legacy novels has a plot-relevant collection of ancient magical royal jewels, including a crown.
In Patricia Wrede’s Lyra, the Crown of Lyra is a powerful magical artifact.
In Andre Norton’s The Zero Stone, the Stone of the title is a Forerunner artifact mounted on a ring.
In Trek’s Elaan of Troyius the woman of the title had a necklace that turned out to be made of dilithium.
In Trek’s Catspaw the shapechanging alien Slyvia wears the same necklace both as a woman and a cat, a visual indicator they are the same.
In Trek’s I, Mudd the androids all wear necklaces with ID numbers, up to 500.
In the novel The World is Round, there’s a ring made of metallic hydrogen. Its plot relevance being that it demonstrates somebody can make stable metallic hydrogen; the effort to discover where and how kicks off the plot.
…there was a pendant, clear, and on a chain, that contained a silver Enterprise.
And I believe that Gary Seven’s dear little kitty, Isis, also wore a gemmed collar.
Sweet little Isis! How I’d love to have her sit in my lap.
And purr.
