Good idea and definitely unique. I hope you continue with it. Consider though, that when filming with a GoPro, or any non-professional camera that uses a small sensor, your images will be too bright and too contrast laden. Filming the shaded side of the boulder and using a reflective panel (collapsible) to profound less intense fill light might work out better. Alternatively, you could open a translucent umbrella that will provide your subject area with a less intense and softer light. As you have pointed out once before, a rock surface is a difficult thing to capture on video. Perhaps moving the camera around a little will offer a more engaging view. The green crystals could be of the Olivine group, such as Serpentine, or perhaps Sphene, indicating that zircon crystals might also be present. I wish more people would undertake intelligent projects like you do. Stuff like this makes me want to get up in the morning.
