Vulcan symbol
The IDIC symbol
Vulcan symbols were images created by the Vulcan people to represent abstract concepts.
The IDIC was the most revered of all Vulcan symbols, according to James T. Kirk. He noted this in 2268 when assuring Miranda Jones that Spock was not wearing it as a taunting suggestion that his mental connection with the Medusans would be stronger than hers. (TOS: "Is There in Truth No Beauty?")
In 2370, Jean-Luc Picard recognized the Vulcan symbol for peace in between those for war and death on the Stone of Gol. (TNG: "Gambit, Part II")