Memory Ball

Greater Memory Balls (highly sought after, highly illegal magic items in the Imperium) are pearlescent multi-colored spheres of a glass-like nature. They range in size from as small as a marble to as large as a human skull. however, most are of a circumference that will fit comfortably in the palm of a child's hand.
These coveted and outlawed items are limited span audio-visual recorders.
Each one is enchanted with a limited time span variation of a clairvoyance spell, the arcane nature of which has been warped and designed to capture and store an audio and visual recording of the goings on in a designated area - conversations, actions, whatever falls within the memory balls 360 range of view. It will record and store the scene, and when activated, will play it back with little to no data loss, unless it has been damaged after the recording took place.
Greater Memory Balls are delicate, light and easily concealed. Prior to recording they are nigh indestructible, despite their seeming fragile nature. Once they have been used to record and store a scene, they become extremely brittle and great care must be taken to keep them from being damaged, or else the recording can be distorted or lost completely. Once a recording has been extracted, the ball returns to its glassy, unbreakable state, ready to be used again.

Lesser Memory Balls are almost identical to their cousins in size and shape, but they are strictly one-use items. Once it has been activated to record a scene and then reactivated to play it back, it resorts to a null state, basically becoming nothing more that a pretty paper weight. While this type of memory ball is also considered illegal, the penalties and fines for use and possession are often times much more lenient than the consequences associated with the Greater kind.
The enchanted nature of both types (Lesser & Greater) of these objects make it appear as though a slow moving storm of color is circling just beneath its textured surface. The reflective exterior of each ball is slightly different or unique, many have raised or grooved patterns as part of their texture. Concentric lines or raised ridges encircling them, or varying spiral, fractal patterns that are pleasant to the touch. It's not unusual to see those who possess them to be running a finger or thumb over them in absent-minded contemplation.

Blackmail, Espionage & Entertainment

Greater Memory Balls are, outside of those in Imperial control, contraband items.
Use or possession of a these types is a criminal act, punishable by heavy fines, imprisonment or loss of life or limb.
Delving Guilds, Delver Sponsors are authorized to handle and use them for the relaying/replay of visual recordings of the Delving Games, as is the Imperium's Office of Special Affairs for purposes of spying or collecting evidence related to criminal acts.
Though great care has been taken to account for all Greater Memory Balls in existence, the exact number of these items is unknown.
While the government does crack down hard on the illegal use of them, there exists a underworld pornographic network that uses and sells these lesser memory ball recordings for profit.