The primary factors on a worry stone are size shape and textures, for interreacting with the nerves of the hand. It should feel good and give a nice massage when moving it around in the hand.

Emerald worry stones: (a mixture of matrix and green beryl) have a soothing effect and help relaxation. They should be processed by scrubbing with toothpaste to get all grit and oils off.
They can be shaped and polished to some degree, but its not necessary for their function.
Sold individually: $0.05/carat + $4.40 s&h.

#1 weight= 375 carats = $18.75 total of $23.15 Length= 56mm width = 38mm depth = 30mm
FABULOUS FIRE PEARLS TECTITE, TEARS FROM THE MOON LEGEND HAS IT, THEY BRING POWER AND FORTUNE TO THEIR OWNERS #2 weight= 295 carats = $14.75 total of $19.15 Length= 43mm width = 34mm depth = 32mm