Graviton
The graviton is the comma 129140163/128000000 = [-13 17 -6⟩. It belongs to the syntonic-chromatic equivalence continuum and is equal to the difference between a stack of six syntonic commas and an apotome ((81/80)6/(2187/2048)), or in terms of classic chromatic semitone, between a stack of four syntonic commas and a classic chromatic semitone ((81/80)4/(25/24)). It is also the schisma times the sensipent comma and the parakleisma times the semicomma. Tempering it out leads to the gravity family of temperaments. Patent vals which temper it out include those for 7, 58, 65, 72, 130, 137, 202 and 346.