An interesting theme that gets brought up on rare occasion in murder mysteries is gemstones said to be cursed. Often this takes the form of a murderer trying to cover his murder with the legend of the curse. Something I think more interesting, that does not get explored nearly so often, is the idea that the curse is fulfilled even when it a man fulfills the curse accidentally.
Let us say that there is some great sapphire, the size of a man’s fist, which was dug up from the ground in India in some ground supposed to be sacred to someone or other, and a curse attaches to whoever defiles the sacred ground by keeping the sapphire for himself. Let us say that it was dug up by three men, and shortly afterwards one, in a fit of greed, murders the other two in order to keep the sapphire for himself. On his way back to England, a fellow passenger discovers the sapphire and murders the last of the gang and steals the stone. Back in England the thief is himself murdered while trying to fence the stone. Unfortunately for the fence who killed the thief, the unscrupulous nobleman to whom he showed the sapphire became obsessed with it despite his inability to pay for it. The nobleman hired some thugs to kill the fence and steal his jewels, then killed them after they delivered the stolen property to him.
Here the sapphire remained until the nobleman died of old age, as he would not show it to anyone out of jealousy, but when he came to die and his nephew inherited the dilapidating estate, the sapphire was found as were the old man’s writings about his beloved stone, including the history of it and the curse that follows it. In these writings the old man attributes his miserable, lonely life to the curse of the stone, but cannot bring himself to get rid of it. This gets widely known and the nephew’s heir murders him to inherit the sapphire, but tries to pin the murder on the curse, perhaps by attempting to disguise the murder as a fake suicide.
When the case is closed and the sidekick says to the detective, “so the curse wasn’t real after all?” the detective can reply, “I wonder, my friend. Does the sapphire need its own hands to enforce its curse? Is its curse less a curse because it uses men’s hands to do its evil?”
It’s a good question. To some degree we’re straying into the territory of Jonathan Pageau and Jordan Peterson, describing the curse as a pattern that follows because of how men react to the gemstone and ascribing agency to it is true at least insofar as people reliably react to it in a particular way.
This did more-or-less come up in a Poirot short story, btw. It was one of the Labours of Hercules, specifically, the Apples of Hesperides. In it there was a chalice which was stolen from an art collector and he hired Poirot to get it back. Deaths had followed it; it had originally been used to poison people with a secret compartment that can hide the poison and release it into the drink, and later people would kill to have the chalice. At the end of the story, when Poirot returns the cup, he begs the art dealer to give it back to the cloister where it had found its way, as there people only used it as a chalice and it was in this way purified by their innocence and deaths would no longer follow it.
This is an interesting theme to explore in detective fiction. I wish it were explored more often.