The soft glow in moonstone is caused by light interference between alternating layers of two feldspar minerals inside the stone, so it moves with the viewing angle and it is brightest in one direction. That means a strand of beads will have some beads showing a strong sheen and others almost none, depending on how each one was oriented when cut.
This is the standard trade material from Sri Lanka and India, unheated and untreated. It is a moderately soft feldspar, so it will scratch if worn alongside metal cuffs.