"It Must Have Been Allotropy"

"The Vanishing Diamonds."
By Charles R. Tanner (1896-1974).
First appearance: Amazing Stories, June 1938.
Short story (10 pages).
Online at SFFAudio HERE (PDF).

"A fortune in jewels awaits Professor Stillwell, discoverer of flawless artificial diamonds. Then the gangsters decide to muscle in—and the diamonds begin to disappear."

Chapter I: "I sometimes think that he is not just exactly human . . ."
Chapter II: "A Startling Discovery"
Chapter III: "Disappearing Diamonds"
Chapter IV: "A New Arrival"
Afterword: "Meet the Authors"

Some of the best science fiction (SF) deals with how technological developments affect the individuals who invent them and the society as a whole in which they live; given enough time a list of thousands of stories (and films derived from them) could be adduced, such as The Time Machine and The Invisible Man, of course, but also such seemingly un-SFnal productions as The Man in the White Suit (which our story prefigures by a dozen years) and Singin' in the Rain.

In today's tale, Professor Stillwell, an intellectual polymath and very much the classic absent-minded professor, quite by accident makes a discovery with the potential of changing society, but especially the economy, in ways no one can predict with certainty—but it's safe to assume it'll probably be catastrophic.

If value depends on scarcity, then abundance diminishes value, a fact of life our accidental innovator absentmindedly dismisses, but one which isn't lost on anybody else: his good friend Clem, an incensed mob of jewellers, a man from the Treasury Department—and this little guy with a tiny red moustache, a snub-nosed automatic in his pocket, and an unhealthy interest in getting rich quick.

Principal characters:
~ Professor Isaac N. Stillwell:
   "Yes, I guess it's diamond, all right."
~ Clement Jordan (first-person narrator):
   "Why, man, there's millions in this."
~ Marjorie Barrett (a.k.a. "The Pest"):
   "I think there's something funny about those diamonds."
~ The T-man (unnamed):
   "Looks like there's going to be a regular convention before the night is over."
~ Jeremiah Small:
   "I knew there was something phony about this, but—making 'em!"
~ Tony the Slip:
   "Well, me and a couple of pals has got interested in them diamonds of yours."

Resources:
- The '30s were a hard time for Charles Tanner; see Wikipedia HERE, a tribute webpage HERE, and his own comments at the end of the story.
- Naturally, Tanner hasn't escaped the attention of the SFE HERE and the ISFDb HERE.
- FictionMags informs us that Tanner produced at least two stories featuring Professor Stillwell, the one above and "The Stillwell Degravitator" (Amazing Stories, February 1941: "Stillwell saw only good in his machine that overcame gravity—until he put it to practical use!").

The bottom line: "Some fool has invented an indestructible cloth. Where is he? How much does he want?"
— Sir John Kierlaw