Glass watering bulbs are hollow orbs that can be filled with water and inserted into plant containers to help keep the soil moist.
Mine is rather plain and dull-looking, at least while doing its duty, lodged in a pot. Inconspicuously, it doles out single drops of water to extend the flamboyant but brief lives of my impatiens, which end up overrunning the container in all their showy glory and obscuring the bulb entirely.
It really sparkles, though, when it’s pulled free and held up to the light.
*BTW: A stained-glass ball held between your readied camera and the burning centre of our solar system may not provide adequate retinal protection against the sun’s harmful rays.