This story is a sequel to The Flight of the Alicorn

Rarity was certain her troubles with magical gemstones had ended, but an unexpected royal visit soon convinces her otherwise. In order to save an ailing Princess, stop an ancient menace, and avert a disaster that threatens the survival of a lost tribe of ponies, Rarity, Blueblood, and a brave group of friends will travel to strange and foreign lands, and into the fathomless depths beneath tormented seas. In her quest to uncover the secrets of the Abyssal Forge, Rarity will have to use all her charm, wit, and skill—and rely on allies old and new—as the unlikeliest of ponies once again attempts to save the world in style.

Part Two of Three
The Adamant Triskelion - Book One: The Flight of the Alicorn
The Adamant Triskelion - Book Two: The Abyssal Forge
The Adamant Triskelion - Book Three: ???

Beautiful cover art by Lucky Dreams.

Rarity's exploits in "Sweet and Elite" set in motion a chain of events that will find the unicorn dressmaker taking part in the greatest airship race in the world, the Alicorn's Cup. Excitement will give way to terror, as Rarity soon finds herself the victim of a plot against Equestria, and shipwrecked far from home with her least favorite stallion, the boorish Prince Blueblood. Rarity will learn of treachery in Canterlot and abroad, and will have search for something of substance beneath the prince's obnoxious veneer as she struggles to not only save herself, but her entire nation.

Part One of Three
The Adamant Triskelion - Book One: The Flight of the Alicorn
The Adamant Triskelion - Book Two: The Abyssal Forge
The Adamant Triskelion - Book Three: ???