Crystal paperweight designed by Alessandro Guerriero for Ritzenhoff, Germany, circa 1990s. This piece belongs to the Ritzenhoff designer series, in which internationally recognised designers were invited to create decorative crystal objects. Alessandro Guerriero is an influential Italian designer and founder of the Alchimia movement, a key group within the radical and post-modern design scene that influenced the Memphis movement in the 1980s. The paperweight is made of clear crystal with a hemispherical dome magnifying a vivid geometric composition of concentric circles in yellow, green, orange, blue and red. The optical effect created by the thick crystal intensifies the colours and gives the design a striking visual depth. Although produced industrially, pieces from this designer series are relatively scarce on the secondary market and increasingly sought after by collectors of post-modern and Italian design. The designer’s name “Alessandro Guerriero – Ritzenhoff” is engraved on the side of the crystal. The paperweight is offered together with its original box and booklet, which further confirms authenticity and enhances collectability. Condition: Excellent condition with minimal signs of age and handling. Original packaging included. A decorative and collectible example of late 20th-century European design.