Diminished Triads: These are chords made up of two minor thirds stacked on top of each other. They consist of a root note, a minor third above the root, and a diminished fifth above the root.
Major Triads: These are chords made up of a major third and a perfect fifth stacked on top of each other. They consist of a root note, a major third above the root, and a perfect fifth above the root.
Minor Triads: These are chords made up of a minor third and a perfect fifth stacked on top of each other. They consist of a root note, a minor third above the root, and a perfect fifth above the root.