Vintage Black Opaque Glass Marble Lot 25ct Ribbon Swirl UV Cadmium Slag #MB15

A distinctive 25-count collection of vintage machine-made glass marbles featuring dense, jet-black opaque glass bases accented with dynamic surface swirls, patches, and slag ribbons. Reflecting the classic output of mid-century American glassmakers, this assembly includes crisp contrast designs in opaque white, sunny yellow, vibrant cobalt blue, jade green, and fiery red-orange layered across deep obsidian-toned spheres. Highlighting specialized batch chemistry from the historic production era, select ribbon elements incorporate mineral-based cadmium formulas that react under ultraviolet longwave illumination to produce a vibrant orange-red glow, while subtle trace compounds yield soft greenish fluorescence against the inert dark glass. This cohesive grouping brings together traditional machine-rolled swirl craftsmanship, stark contrasting color runs, and coveted reactive formulations prized by vintage marble and art glass collectors. # MB15