Phantom (in mineralogy and crystallography) - sometimes, during the growth of crystals and a change in growth conditions, microscopic inclusions of other minerals, gas-air inclusions or a change in the color of the mineral itself remain on the crystal. In a transparent crystal, they leave traces - the shape and size of the former crystal on which they formed.
You can see a stone with a phantom for sale and buy it in the Minerals of Russia online store.