Spirit

Spirits, also referred to as ghosts, are the essences or souls of the deceased. When a person dies, their souls are collected by the Angel of Death and taken to the afterlife. However, not all become spirits as some choose to be reincarnated, thus starting a new life after death.

Some spirits remain on earth when they are unable to move on. Usually this occurs when a person has unfinished business in life, such as being unable to accept their death or when their death was so quick that they still believe themselves to be alive. Spirits may also remain on earth until justice had been done or when they seek avenge themseelves. Evil spirits may remain on earth to avoid purgatory.

Appareance
The appearance of spirits has greatly varied over the course of the series. They may be transparent and hazy such as in the case of Elias Lundy or corporeal as with Charlene. Some ghosts like Rick and Nathan Lang are transparent but crystal clear, not hazy. Mark Chao, the first ghost encountered in the series, was invisible to everyone except magical beings, but to those he appeared undistinguishable from a live person. In "I Dream of Phoebe" when Phoebe and Paige became ghosts Chris stated they could haunt anybody they wanted.

Ectoplasmic Residue
There is a potion Piper used in "Love's a Witch" that can determine if there is ectoplasmic residue on an object. With the correct ingredients, once the suspected object is dropped within the potion, it will glow white if ectoplasmic residue is present.

List of Spirit
In Blessed Only
 * Patty Halliwell
 * Penny Halliwell