Opened my necklace stand in Gimp and created a path the shape of HALF of the necklace (see example in xcf attached).
Set RJKD pearl brush (or brush you make) size 40 px, spacing 100 Dynamics – velocity tapering.
New layer - stroke path (set to Stroke with a paint tool – brush and check emulate brush dynamics).
Duplicate layer 4 times, turn off background layer (stand) – merge visible layers.
Erase back of necklace to collar line
Duplicate layer and flip horizontally.
Line up layers as required (may be worth zooming in to get good align).