Luxury product photography of a white gold ring with a pear-shaped ruby gemstone and baguette-cut diamond side stones composed on the edge of a polished green marble cube pedestal. Strong directional studio illumination creates star-like reflections on the ruby facets and prism-like rainbow light refractions across the marble surface. Backdrop is a deep emerald green gradient studio environment. Elegant high-contrast illumination, crisp reflections, high-luxury jewelry ad brand campaign aesthetic, hyper-lifelike gemstone rendering, 8k resolution.