Constructive emotional experiences are strongly related to effective learning. Yet, it is challenging for teachers, researchers and students alike to understand the emotions experienced in the classroom setting. Advances in wireless and sensor technologies open up possibilities for better supporting emotions. However, little work has explored how affective technologies in the classroom might operate. This paper describes a study where 15 high school students used the Subtle Stone: a tangible technology designed to support students' active emotional communication in the classroom. We report on how the students used and experienced this technology, and the values they demonstrated through this use: flexibility, privacy, agency, voice and reflection. We conclude by examining future possibilities for affective technologies in the classroom. Author Keywords Emotional communication, emotion, affect, classroom, learning, Subtle Stone, affective technologies ACM Classification Keywords K...