The Starfleet Academy ring was a silver ring given to graduates of Starfleet Academy. The ring's inner circle was decorated with the Federation flag symbol and the words "Starfleet Academy", while the outer circle had the words "United Federation of Planets" and the graduation year.
Section 31 agent Thomas Harewood used a ring provided by former agent John Harrison as a bomb. Harrison forced Harewood to walk to work at the Kelvin Memorial Archive and drop the ring in a glass of water, igniting the bomb and destroying the facility. (Star Trek Into Darkness)