Clear. Something like birdsong, almost like a voice. The diamond sang and would always sing.
Nobody knew how or why.
They say it was found by a rogue traveller in the rainforest, who had walked past the trees and his eyes had been blazed with a beam so white and so strong he turned towards it. He marched out of magnetism he took for curiosity, and found it perched in a tree amongst birds of paradise. It was flawlessly cut and heavy as a pebble in his hand, and as it pressed against his palm he could have felt the tiny vibrations of the throatless voice, if he'd stopped to notice.
Many people stole it and sold it, and their lives felt quiet and cold when they let it go.
It was a myth and a curiosity. The bloated aristocrat who owned it for twenty years and wore it in a pendant to every party (where she had to talk over it) held it in a room on the very farthest tip of her estate. She hated the sound and loathed wearing the damn thing, and even so far away she'd swear she could hear it, taunting her, interrupting the self-obsessed whirl of her thoughts with its lilting song.
When the opportunity came to pass it on came, her greed gave way to her frustration. Her son's new wife, whom she hated only slightly more than the diamond, was suffering under the truth of the aristocrat's disapproval. The aristocrat saw the gorgeous opportunity to both appear vastly generous while making the new girl's life secretly miserable with this sparkling curse, and she gave the diamond to her daughter-in-law with manic flourish.
As the aristocrat lay down in bed that night, knowing full well the damned thing was traveling further and further away in a padded box in her daughter-in-law's arms, she wept. Because she knew the diamond was gone, but she could still fucking hear it.
The Singing Diamond is a completed short story that I'm not sure is strong enough to put into my collection. It's hard to make a compelling story from the point of view of an inanimate object. It's gone through several edits and... I still don't know.