THE GEOLOGY OF GRAVESTONES

Along with black cats, witches and jack-o'-lanterns, cemeteries are iconic symbols of Halloween—and for good reason. Shrouded in mystery, superstition and folklore, they can elicit feelings of foreboding and fear.

- BY STEVE VOYNICK

Shrouded in memories, mystery, superstition and folklore, they sometimes elicit feelings of foreboding and even fear. Wikimedia Commons

For most people, cemeteries—the word stems from the Greek koimētērion meaning “sleeping space”—are places of quiet and solitude for contemplation and the commemoration of the dead. But as repositories of history, culture and art, cemeteries also draw historians searching for clues to the past, antiquarians studying gravestone styles and genealogists tracing ancestral roots.

Geologists and rockhounds are also attracted to cemeteries, but for different reasons. With their rows of silent headstones, cemeteries are open geology textbooks that are literally written in stone. And they provide a great opportunity to study sedimentary, metamorphic and igneous rocks that have been cut and polished, and that display a wide range of colors, textures and stages of weathering.

Far left: This old sandstone gravestone shows severe weathering in the form of "slabbing"separation along natural bedding planes. Wikimedia Commons.

Near left: Coarsely crystalline, multi-colored gneiss, sometimes used in gravestones, shows prominent bands and swirls that formed during the semi-molten stage of the metamorphic process. Wikimedia Commons.

THE EVOLUTION OF GRAVESTONES