Rocks All Around Us

Whenever I venture out in the world, I check out the rocks in my environment – they are all around us in natural outcrops or layered onto the buildings in our towns and cities.

As a “rock person”, in addition to admiring rocks at many archaeological sites, I have discovered that high-rent office buildings, museums, and luxury hotels frequently have impressive stone interiors and exteriors. In tiles on the floor or in wall panels, on reception area counters and dining room tables, in elevators, and even the stall dividers in public bathrooms, one can find an intriguing variety of rough and polished rock.

In the past when I have closely examined beautiful marble floor tiles, I have been asked by hotel staff if I have lost something. I attract puzzled glances when I stand in an elevator with my nose almost touching a polished granite wall panel. (I know I’m a bit weird – I’ve been that way my entire life.) While hiking, I carefully observe the rocks and try to resist picking up too many samples to add to my ever-growing collection.

Ultraviolet light and exposure to oxygen affect human skin – definitely apparent from looking in a mirror as decades of birthdays accumulate. Many people don’t realize that rocks are also affected, especially in high altitude mountain environments like the Andes. Most rocks that have been exposed to our atmosphere for any length of time become weathered by wind and water, and an outer crust with a slightly different color and hardness develops. Ditto for human skin. Mineral identification is easiest in un-weathered, or fresh, rock. When geologists are outside doing fieldwork, an essential piece of gear to carry is a rock hammer. This handy tool is used frequently to smack off pieces of rock to examine the un-weathered fresh surfaces with a magnifying hand lens. While hiking along the Inca trail to Machu Picchu, I was strongly tempted to break off corners of stone blocks on stairways and temple walls just to inspect the minerals in a fresh rock face. I resisted this urge, of course; I would never harm ancient landmarks. But I also must admit it helped that I’d left my hammer at home.