Bead

1. The globule of precious metal obtained by the cupellation process in assaying. Webster 3rd
2. In blowpipe analysis of minerals, a drop of a fused material, such as a "borax bead," used as a solvent in color testing for various metals. The addition of a metallic compound to the bead will cause the bead to assume the color that is characteristic of the metal. See also: blowpiping AGI

Source: Dictionary of Mining, Mineral, and Related Terms