Which chord is characterized by two major thirds?

The chord characterized by two major thirds is the augmented chord. An augmented chord is constructed by taking a root note and stacking two major thirds on top of it. For example, if you take C as the root, the first major third would be E (the note a major third above C), and the second major third would be G# (the note a major third above E). This results in the notes C, E, and G#, which form the augmented chord.

In the context of the other chord types, a major chord is made up of a root, a major third, and a perfect fifth, which does not include the stacked major thirds required for the question. A diminished seventh chord consists of three minor thirds stacked together, leading to a very different sound and structure. Finally, a minor chord contains a root, a minor third, and a perfect fifth, which again does not meet the criteria of having two major thirds.

Overall, the augmented chord's unique structure of two major thirds distinctly sets it apart from these other chord types.