The question of Herncastle's grudge and his will is one of the first mini- mysteries within the larger mystery of The Moonstone. Before the main crime of the theft of the diamond is even committed, detective work is introduced into the novel by way of Franklin's research of the history of Herncastle and his diamond. Franklin posits a series of logically related questions in much the same way that Sergeant Cuff will approach his investigation of the diamond theft.
Franklin concludes that the three Indians that Bettredge and Penelope have seen on the Verinder property are probably in search of the diamond. He reaches this conclusion by reasoning that the stipulations in Herncastle's instructions to his lawyer show that he was protecting himself from persons who wanted the diamond for non-commercial reasons. This theme of the commercial value of the diamond versus the spiritual value persists throughout the novel. The diamond has a flaw in the center and thus would be worth more cut up. But to the Indians, the diamond is only spiritually symbolic as a whole—a whole that rightfully belongs in its setting in their idol. Betteredge and Franklin show themselves to be instead compelled by the economic value of the diamond, when they cannot resolve to keep the gem from Rachel, despite the probable danger that comes with it. Betteredge at one point suggests disposing of it, but Franklin agrees to do so only, "if you [Betteredge] have got the value of the stone in your pocket," and Betteredge accedes to this reasoning.
In these chapters, belief in the non-economic value of the diamond is related to belief in the curse that the diamond might bring with it. The introduction of such non-concrete or unrealistic possibilities is accompanied by discussion within the narrative of realism and the fantastic. Betteredge's narrative calls attention to the exotic aspects of the story as when he remarks, "our quite English house suddenly invaded by a devilish Indian Diamond Who ever heard the like of it—in the nineteenth century, mind; in an age of progress, and in a country which rejoices in the blessings of the British constitution? Nobody ever heard the like of it, and consequently, nobody can be expected to believe it. I shall go on with my story, however, in spite of that." Collins addresses a different side of realism through the character of Franklin. Whereas Betteredge is sympathetic to our potential disbelief, Franklin shows elitist scorn for those whose imaginations cannot extend beyond the everyday: "Nothing in this world, Betteredge, is probable unless it appeals to our own trumpery experience; and we only believe in a romance when we see it in a newspaper." The Moonstone is, of course, subtitled "A Romance," and the comments put in both Betteredge's and Franklin's mouths can be read as winks to us from Collins himself.