When a Clear Quartz Crystal encloses a fully formed one inside it, this is called a Manifestation Quartz and it's a rare thing indeed.
The inner crystal is the vessel for the idea you wish to manifest - much like a child in the womb except the walls are clear. The outer quartz nurtures and protects the growth of that idea until the time is ripe for it's birth.
There's always a double message with this precious stone. Yes the inner Crystal represents the idea that you want to manifest. But also it represents you living and growing in the embrace of the Universe.
Which brings us to the crux of all manifestation - your goal is part of you and the Universe, Choose wisely, for above all you must be open to grow and change in order to be able grasp that which you wish to manifest.