A rare amethyst-colored crystal tabletop object designed by Joe Colombo for Arnolfo di Cambio in the late 1960s. The design, characterized by a perfectly hemispherical shape and a central cavity carved with great formal purity, fully reflects Colombo’s experimental style: minimalist, futuristic, and strictly functional. The crystal’s internal texture creates sophisticated optical effects and light refractions that highlight the quality of the material, crafted from crystal containing over 24% lead in accordance with Arnolfo di Cambio’s high production standards. It retains the original labels from that era, a feature that reinforces its authenticity and collectible value. An important piece of radical Italian design, intended for collectors and enthusiasts of the finest 20th-century design.