Golden obsidian is a variety in which the glass began to crystallise as it cooled, or in some cases contains oriented mineral inclusions — either way, the result is a metallic gold sheen that shifts as the light moves. It is distinct from the rainbow obsidian that shows colour banding.
The two Pixiu beads are carved rather than moulded, so they sit slightly proud of the strand. Because the flash on golden obsidian is directional, the beads on a good strand are oriented when strung so the sheen lines up; the two carved beads break that up deliberately.