This is a wrapped Fluorite octahedron on a chain made with small chrysocolla beads.
The photos don't do the fluorite justice. It's a blue/green color, like a turquoise.
Fluorite is said to improve concentration and decision making. Chrysocolla is said to promote level headedness, encouraging clarity of thought and a neutral, cool attitude during turbulence.
While I can't say if the stones actually do any of those things, they do look lovely together.