Stone of Beta Adventuring (1)  

 

These drop from non-trivial mobs on the beta server. The drop rate increases the higher the /con of the mob compared to you, ie a light blue mob drops them rarely but a red con mob will drop one 50% or more of the time.

They can also be given out by GMs and are were added as quest rewards in SoF beta for testing tradeskill combines.

When handed in to Old Man Thorren in PoK they give around 4% AA exp each. A tally is kept of how many you hand in, traditionally with a reward given out after beta if you reach a certain threshold.