On a cloudy Sunday morning in Hyderabad, a group of hikers makes their way across a sprawling university campus, first on paved roads lined with colorful bougainvillea and then through prickly shrubs. Their destination: pathar dil, or heart of stone, a natural formation of four boulders that stands as tall as a two-story building. Upon reaching it, the hikers rush to take pictures and try to squeeze through the gaps in the boulders, “slicing through the heart,” one of them jokes. One of the oldest members on the excursion is…