Bib: multiple strands of beads, each one longer than the strand above it.
Graduated: beginning with the largest bead in the center front, the beads decrease equally in size on each side of the center bead towards the clasp at the center back.
Uniform: all beads are within .5 mm of one another, a naturally occurring variation.
Lengths*
Choker: 15-16 inches. Worn above the collarbone.
Princess: 16 to 18 inches in length. Hangs just below the collarbone.
Matinee: 22 to 24 inches in length. Hangs just at or just below the bust.
Opera: 30 to 32 inches in length.
Rope or Lariat: 45 inches or longer. Can be worn as-is or wrapped to create a two-stranded choker.
*These lengths are for a woman of average build. If your overall build is larger or smaller you'll want to adjust accordingly.