Comparisons.

Labradorite vs moonstone how to tell them apart in beads

Both are feldspars. Labradorite shows directional blue to gold flashes from a dark gray body. Moonstone shows a soft blue or white glow from a milky body. What many sellers call "rainbow moonstone" is actually white labradorite. We sort by body color first, then watch how the sheen turns on and off as we tilt the strand.