CONCHO RIVER PEARL Members of the Tom Green county Historical Association were told that pearl-diving once was a big business in the Concho river. Many families of the San Angelo region still own beautiful specimens taken from river mussels. Ords show the first pearls were dis covered in 1888. Building of dams, plus the inroads of floods, droughts, and constant high mortality in mussel population have just about eliminated all chance of finding pearls now.