This is a 70 mm leaded crystal ball; it can be used for scrying or as an altar piece.
To use a scrying sphere, gaze into the sphere, usually off-center, at an angle, or the reflection of another object in the sphere, such as the moon or a candle. As you gaze, you may fall into a light meditative state that allows you to “see” images for divination purposes. Some report that the images appear in the mirror; either the images obscure the “real” reflection or the “real” reflection morphs into the images. But most report that the images appear in their minds. These may also be associated with other sensory information, such as words and different sounds, scents, and feelings of warmth or cold, but the information received is usually strictly visual.