Moldavite is one of those stones you have to be especially careful with when you endow it with a tasking-and you DO want to take the time to give it a specific task! Here's why:
As djoya said, it is about transformation. Specifically, shaping things. It's good for those instances when there's something about YOU that you don't like and want to change, or remake yourself. The thing is, you must be VERY specific. You never want to task it by saying: I want to be more like this person or that person because what you'll get is EVERYTHING that person is. The whole package. All the good but all the bad too! You would rather want to take that specific attribute you are looking for and task the stone to help bring you those specific energies and vibrations.
If you do not task a Moldavite stone it tends to lock you in the position you're currently in-something like being caught in a rut. That's why you don't want to leave it without a specific task. It can also cause you to 'drift' or remain in flux and hence confused, off-balance, un-centered, mallable to any and all outside influences, etc. That is also why you shouldn't use more than on of these stones at a time. You can see how they might tend to cross each other up and create some havoc.
Anyway, hope this helped some!
We have seen what Power does.
We have seen what Power costs.
One is never equal to the other.