Gem Shards

"Gem Shards" are magical items that first appeared in "Frybo" and also in "Secret Team" and "Keeping it Together". They are the shattered remains of broken Gems that still contain remnants of the original Gem's form.

"Frybo"
Pearl tried to explain to Steven that ''"These shards have a powerful partial consciousness that has been harnessed by Gems throughout history in order to create semi-sentient drone soldiers with the capacity to follow basic orders. Gems once created an army of these drones, but found their obedience waned as the shards overdeveloped inside their uniforms and turned on their commanders. You see, any shard inside any sort of container could become a monster!" ''An example of this is when Frybo turned on Steven and Peedee Fryman, which is why the Gem Shards must be kept away from all clothing and other items to avoid other dangerous situations.

Since these Gem Shards did not try to regenerate spontaneously after being released from their bubble (like shards in later episodes do) it is possible that these were enchanted or somehow altered after their Gemstone was shattered to alter their function, overriding natural Gem behavior.

"Secret Team"
Pearl, Amethyst, and Steven accidentally popped a Rose Quartz bubble containing a mass of mixed Gem shards, which regenerated into non-sentient disembodied arms and legs. After defeating and collecting the scattered Gem Shards, Steven bubbled them and they attempted to keep it a secret from Garnet, but failed. The Gem Shards attempted to reform but due to not being a complete Gemstone each shard reformed into a single limb such as an arm or a leg.

"Keeping it Together"
While in the Kindergarten, it is revealed that Gem Homeworld is forcing the gem shards of fallen rebel gems from the war to fuse. The shards are able to take on a form, but the generation only results in limbs spliced together in unnatural or random ways. The former Crystal Gems that comprise The Cluster can regenerate, but the process causes them obvious pain. Whether or not the Cluster regenerates by will is unknown; in its debut moments its constituents are seen trying to escape the fusion but that might just be spontaneous regeneration like that of the Gem Shards in "Secret Team".

Trivia

 * The Evil Spirit Scroll was painted using pigments from crushed Gem shards.