Hidden Star by Corinne Joy Brown, a story about a Southwestern family uncovering their Jewish ancestry during the Spanish Inquisition. Which "Hidden Star" story were you looking for? The Nora Roberts romance with the blue diamond? The fantasy with the hidden princess? Something else? Let me know and I can get you more specific details. Review of Hidden Star (9781460275788) - Foreword Reviews
She seeks help from Cade Parris, a sharp private investigator who instantly falls for her despite the danger. hiddenstars1
Bailey James is a woman suffering from amnesia with no memory of who she is. She finds herself in big trouble, holding only a satchel filled with cash, a gun, and a massive blue diamond. Hidden Star by Corinne Joy Brown, a story
Together, they must navigate the mystery of her identity while staying alive. Other possibilities from your search results: The fantasy with the hidden princess
The Hidden Stars (Rune of Unmaking #1) by an unknown author (2004), a story about a "hidden princess" and a tyrannical dark queen.
A story named "Hidden Star" by Aina on Wattpad/Inkitt.