Surrounded by Cordry rocks
Cordry rocks were pebble-like objects installed in Starfleet vessels. Starfleet engineers, such as Andy Billups, considered cordry rocks essential since their non-centrosymmetry disrupted the charge leptons in the isolinear pathways of the main deflector, which caused other things to transpire. However, they could also be dangerous projectiles when damage occurred. Jack Ransom was not fond of them for this reason.
In 2366, these rocks were among the debris that fell from the ceiling of the USS Enterprise-C and killed Captain Rachel Garrett. (TNG: "Yesterday's Enterprise")
Sometime in 2382, the USS Cerritos's supply of cordry rocks was replenished. (LD: "Upper Decks")