"When the rays of the mind are scattered over diverse objectsyou get pain. When the rays are gathered and collected bypractice the mind becomes concentrated and you get Ananda(bliss) from within." - Swami Sivananda
Pure or “Sattvic” thought is the result of a mind that is steady and single-focused. It is an unruffled state of the mind, unaffected by worldly desires and difficulties where there exists spiritual ananda (bliss), peace, contentment, fearlessness, steadiness, inspiration, intuitive perception, and absence of anger, egoism and raga-dwesha (likes and dislikes).
Pure thought is attainable through meditation and concentration but the challenge is to find the right fixation for the mind. The mind assumes the shape of any object it intensely thinks upon, and hence it is important to subdue the mind, rid oneself of mental perceptions and use the pure intellect to still the mind, to reach a stage where there is no touch with any sense-object.