This fascinating sundial uses a crystal as the gnomon (no-mon). Sunlight shining through the cyrstal will create a bead of light that points to the time on the clock face. Hold the piece so the Sun icon at the top points towards the South, and tilt to allow the Sun to shine through the crystal. The sunlight will pass through and point to the current time on the clock face. Please note the image of the sundial being held up to the sunlight is to demonstrate how it works - the actual color will be the one you select when purchasing. Thank you!