Mineralogical Marvels

May-June 2010

Blue-green aurichalcite on reddish gossan, from the Ojuela Mine in Mapimí, Durango, Mexico

Anhydrite from the Naica Mine in Chihuahua, Mexico

Here quartz has replaced anhydrite, in the process taking on the latter's shape to create a pseudomorph. The specimen comes from Ametista Do Sul, Rio Grande Do Sul, Brazil.

Green arsentsumebite has created a pseudomorph of mimetite, a generally colorless mineral (notice the small pale spot remaining at the extreme upper right). The specimen comes from the Tsumeb Mine in the Otjikoto region of Namibia.

Purple crystals of fluorite, intergrown with barite, from Berbes, Oviedo (Asturias), Spain

Calcite scalenohedrons (six-sided polyhedrons) with red hematite inclusions from the iron mines of West Cumbria, England

A rhodochrosite rhombohedron on quartz, with brown flecks of hübnerite in the foreground, from the Sweet Home Mine in Alma, Park County, Colorado. Each edge of the rhombohedron is about two inches long.

The edges of this rhombohedron crystal of rhodochrosite from Pasto Bueno, Ancash, Peru, measure roughly eight inches each.

A large botryoidal (“resembling a bunch of grapes”) mass of Smithsonite from the Kelly Mine, Magdalena district, Socorro County, New Mexico

A prismatic crystal aggregate of stibnite from the most famous mineral occurrence known in Japan, the Ichinokawa Mine in Saijo, Ehime Prefecture

Spiky orange crystals of calcite with barite crystals, from the Minerva #1 Mine in Hardin County, Illinois

The Harvard Museum of Natural History’s mineralogical collections offer visitors a glorious display of shapes and colors, as the photograph of crocoite in the May-June issue makes clear. Here are a few more specimens to enjoy, with caption material provided by Carl A. Francis, associate curator of the Mineralogical Museum.

The photographs were taken by Patrick Rogers. For examples of his work as a portrait and wedding photographer, see his website: www.IAmWhatISee.com. His job at the University is as evening imaging supervisor in the Harvard College Library's Digital Imaging and Photography Services, where he may find a medieval illuminated manuscript or an antique map of the world in front of his lens. Extracurricularly, he explores the Museum of Natural History. "It is easy to spend hours there in quiet reflection," he says, "getting a glimpse at the evolution of this planet over eons as represented by the variety of rocks and minerals in this collection."