I really like the approach that you took -- drawing all the primitives first and then moving them around.
On your next project, you might want to use the color function to help the viewers see each piece separately.
Also .. its never too early to teach people to use constants (called variables inOpenSCAD), rather than hard-coding numbers. If you/they ever resize the necklace for someone else, it is nice to only have to change numbers in one place.
Otherwise, very nicely done and simple enough not to scare people off.