Yes. Glass microspheres not exceeding 1 mm in diameter, including those used in retroreflective road-marking paints and thermoplastics, classify under subheading 701820. The 1 mm diameter ceiling is a hard classification threshold; larger glass spheres or beads used in other applications may fall under different headings.

Glass imitation stones are made from ordinary or lead glass and are classified under 7018 based on their glass composition. Synthetic precious or semi-precious stones — such as synthetic ruby, sapphire, or cubic zirconia — are crystalline materials produced by controlled growth processes and classify under the headings for precious or semi-precious stones, not under the glass chapter. A material analysis or manufacturer's certificate confirming glass composition supports correct classification.