This specimen began as a 'stick' of laumontite, which became coated with white, crystalline prehnite. The laumontite subsequently dissolved or otherwise disappeared, leaving a distinct cast of prehnite retaining the shape of the original laumontite (i.e. an epimorph, which is a type of pseudomorph). Excellent condition. As mounted on its black acrylic base it fits into a standard thumbnail 'Perkie' box. Easily dismounted if desired because, for example, you'd rather mount it on a clear, colorless acrylic base...?