I only have one of these left. This is the biggest one and heaviest. 
Roughly 2 inch wide(although it's round) and 5.6oz

This is a rare and special stone, from Egypts white sand desert. These are known and the whisper stone also, you whisper what you need help with and let it attract it to you. Simple requests, even giving it a candle flame to feed off is recommended 

This was one I got from the previous Order I was part of for years and have utilized it in just about ever magickal working I've done. after time, it's a stone to share or pass on when you feel it's time, I've had it for about 12 years. 

Larger pieces of Authentic prophecy stones go for $110 and up.