I know they say they found it by hiking up into some seluded valley. If you hike up into the hills around San Carlos, it's there lying on the ground, so it makes sense it's on the beaches, too. The black of the stone is somewhat translucent, almost like jade. The green orbs appear to be softer material since they have weathered a bit more into slight depressions on the stones. Guess I'll need to be careful of those spots when polishing at home.