Usually when I buy Phantoms they are polished completely with a flat base, these are a left in their natural form and the faces & sides are polished to better show the Chlorite Phantom inclusions. These are from Brazil and are some of the nicest ones we have had.
Phantom quartz is a variety of quartz crystal, that forms over pre-existing crystals. The included crystal is visible due to some variation of minerals or quartz, making the boundary of the included crystal visible. Such crystals display the outlines of numerous smaller crystals, known as phantoms, that take shapes or layers within.