•3He: Observed in oldest meteorites, also observed in radio with the equivalent of 21-cm hyperfine transition (e.g., in planetary nebulae).  Values are in range of [3He/H] = 1.2 to 1.5 x 10-5.  Destroyed in stars like D, but tougher than D, and actually created in stars when D is destroyed.  More complicated than D.