Might be Joan D. Vinge's Cat series. The books are: Psion, Catspaw, and Dreamfall. The series premise is that there are human-alien hybrids that have telepathy to varying degrees. These "Psions" are treated, well, like pre-civil rights-era Blacks in America. The first book, Psion, is set on a mining colony where the Psions are being used as slave labor. The main character, Cat, gets caught in the middle of a violent conflict between Psions and the "regular" Human coprporate-government. In the second book, Catspaw, Cat is hired by an insanely rich corporate family as an extra security measure (because of his telepathy).
I don't see much about an earring, 'cept for this in the second book (Catspaw):
As I passed the bathroom mirror, a sudden flash of green caught my
eye. I stopped, looking at myself, turning my head - saw the light wink
again. My ear. I reached up, touching it, with a slow smile starting.
There was an earring in my ear, one I’ d never seen before. Green
glass, catching the light when I moved, like a cat’s eye. I knew I
hadn’t put it there… I figured I knew who had. I stuck a drug patch
behind my ear, and went out of the room.
“That earring. I wouldn’t wear it again, if I were you. Particularly
not around Charon.”
My hand went to my ear, covering it, protecting it. “Why not?” Not
quite able to keep all the tension out of my voice. “It’s only a piece
His lips pulled up. “It’s an emerald, you fool.”
I stared at him, still touching my ear. “What-?” He’d scanned its
density just by looking at me.
He looked at me now, and shook his head again. “You’re lying about
where you got it, too. It carries a taMing registry code; it belongs
to Lady Lazuli.”
My hand dropped to my side. I turned and went out the door. I felt his
eyes following my back as I crossed the endless, lifeless room beyond.
It's so obviously out of his price range, it causes a fair amount of trouble.