Augmented and diminished chords are not as common as major or minor chords, but it is still important to learn them. They occur in many pieces of music as a way of creating tension before resolving to either a major or minor chord. Listen carefully to these examples to hear the difference in sound between augmented and diminished chords.
This example uses arpeggios of all four types of triads - major, minor, augmented and diminished. Pay careful attention to the fingering.