Bangles

Design:
These are "Rainbow Bangles" or "Aurora Borealis (AB) Rhinestone Bangles". They feature multiple rows of small, iridescent stones, likely cubic zirconia or American diamonds, set closely together in a band. The design is typically non-adjustable and meant to be slipped on. 
Finishing:
The finishing likely involves a metal base, possibly silver or gold-plated alloy, with a high-polish to enhance the sparkle of the stones. The stones themselves have an "Aurora Borealis" or "Rainbow" finish, giving them a multi-colored, iridescent shimmer. 
Material:
The primary materials are likely a base metal such as silver or a durable alloy, and the stones are typically Cubic Zirconia or American Diamonds, known for their sparkle and resemblance to real diamonds.