A Rainbow on the Wall

I scrambled up to the wide wooden windowsill right past the big leafy fern. There was a glass crystal hanging from a white string, spinning very slowly in midair! When I bumped it with my elbow, it suddenly scattered bright specks of pink, green, and blue all over the white wall. I tried to catch a purple spot on the paint, but my hand just pressed flat against the cool wall and the color jumped right onto my palm! Is it paint, or is it light? I nudged the glass again to make all the little dancing patches whirl around.