Hessonite garnet… maybe. Have you considered it might be a zircon?
I am sure those with the appropriate credentials will offer some
assistance… but high RI and brownish red… sounds like zircon.
Hessonite is relatively rare… brown[ish] is a fairly normal color
or Zircons… hitting towards the red side is more unsual, but
Zircons do go that way.
Brown is really not something I would associate with hessonite…
orange like… not brown.
Then… I ain’t no expert here.