...and I've got big hands.
In Ratanakiri, Cambodia, they measure these stones by the kilo. The better the color and overall quality, the higher the rate. Miners get between US$5-10 per kg. Then gems are then cut, fit in jewelry and sold in Ban Lung or Phnom Penh for much higher prices.
Are you planning to visit Cambodia? Check out Insight Guides Laos & Cambodia and Thomas Cook Travelers Cambodia. I undated both current editions myself, and so give them my personal endorsement. Click on the images below to view the books on Amazon.com.