cavansite var. Pentagonite - Wagholi, Poona, India
  
 Pentagonite from the Wagholi Quarry near Poona, Maharashtra, India. Pentagonite, a rare orthorhombic variety of cavansite, is certainly one of the most spectacular mineral discoveries of recent years.
 The mineral was named in 1973 by the Americans Lloyd W. Staples, T. Evans and James R. Lindsay. They named it after the pentagonal crystal twins. Pentagonite occurs in the cavities of volcanic rocks and is often found with zeolites such as heulandite, but never with stilbite. The best-known sites are in the Indian state of Maharashtra.