Stone sphere is basic, one power fractal for color (both high and low colors applied and unclamped ) and then the reflective shader follows with ray traced reflections turned on, low roughness 0.015 , highlight intensity 0.24 and IR of 1.7 and overall reflectivity .6
What you may be detecting is reflections of my secondary lighting. In addition to the normal sun, there is a luminous background type sphere with an HDR lighting file providing extra light via luminosity to the scene. The HDR sphere is set to be not directly visible but the HDR image is exactly reflected in the surface of the stone ball.