the.com/pearl
the only gem made by something alive, and only when it's annoyed.
means A smooth, lustrous, usually round gem formed inside the shell of an oyster or other mollusk, prized for its iridescent beauty.
from From Old French 'perle', from a Latin source — possibly 'perna', a word for a leg-of-mutton shape used for certain shellfish, or 'pernula', a little version of the same. The path is murky enough that scholars hedge, but the shellfish connection is old and fitting: the name traveled with the creatures that make the thing.
originOyster's response to an irritating intruder inside
natural rarityRoughly one in ten thousand wild oysters yields one
acid weaknessVinegar dissolves them; Cleopatra allegedly drank one
birthstoneJune's gem, the only one needing no cutting
layersMade of nacre, the same stuff lining shells