Every person who starts investigating rocks falls in love with the rock hammer. The hammer is such a fine tool for opening up rocks, it makes the task feel as easy as opening up cookies. And we know how irresistible cookies can be. But let me make the case that we should learn and practice restraint with our newfound powers.
I have begun thinking of my hammer the way police officers think of their firearmsa tool to be used last.
The purpose of the hammer is to break rocks. And what is the purpose of breaking rocks?
For geologists both amateur and professional, there are basically two reasons to break a rock:
1. To expose a fresh rock surface.
2. To collect a rock sample.
The benefits of those are self-evident and familiar. But there are at least three reasons not to break a rock:
1. It might cause injury.
2. It would damage a natural feature.
3. It's not necessary.
Let me discuss those in order. I remember a field trip I took in 2005 where all three reasons came up. At one stop we visited a small, isolated outcrop of metamorphic rock about the size of a living room. The leader spoke about the outcrop, and then we went to examine it.
Hammering Can Cause Injuries
Several people took out their hammers and started whaling away without looking around. Rock splinters sprayed my face. I wear glasses, so I was OK, but as mother always warns, "sooner or later somebody is going to get hurt."
Instead of making careful, individual hammer blows, some of the people on that outcrop acted like it was a gym and whacked away nonstop.
Nobody used a chisel that day, thank goodness. Chiseling has actually given me more bruises than straight hammering.
But hammering can be done safely, and the basics of safety are simple, so I'll point you to a separate article about that.
Preservation of Natural Features
The old days are gone when we could treat the outside world as an endless resource. Today, all natural features, including rocks, are in finite supply. The outcrop in that 2005 field trip was certainly finite.
Owners have legal rights over their rocks that they can enforce and that hammerers must respect. Some of these rights are very strict: public parks generally forbid any disturbance of rocks. Or they can be lax (Bureau of Land Management and National Forest lands are generally open to personal collecting) or vague (very few people get in trouble hammering on a public roadcut).
The natural features in a national park are there for the park's owners, who are the people of the United States, and its users, who are the people of the whole world. Everyone who comes to Yellowstone deserves to see Old Faithful geyser, and no one deserves to collect pieces from it any more than they can throw boulders into it for their own amusement. (Geysir, the natural feature in Iceland that gave its name to all geysers, was ruined for centuries by visitors doing just that.) Geologists can practice their science in national parks, but only with permits and stringent guidelines that assure they leave no trace.
Users have more options in other settings. Visitors to U.S. public lands can collect rocks for personal use, and geologists can hammer on outcrops. But a visiting geologist may not know that a distinctive outcrop has long been used by professors as an outdoor classroom. A safe general principle, then, is to treat natural features as respectfully as if they were Old Faithfulto treat them as if they were unique and pristine.
The outcrop in my 2005 field trip was distinctive, as our leader explained. We weren't told to stay off it, and it sat in a neglected corner of a public institution's property. But a hundred years of repeated visits could reduce it to rubble. If we had really wanted to sample it, we could have hammered already-broken fragments, non-visible surfaces, or nearby exposures. Indeed, one member of the group did just that, and she gave me a piece of amphibolite to take away. I didn't need to damage the outcrop to educate myself or you.
Hammer Last, Not First
OK, hammering can usually be done safely and with respect for the natural feature being hammered. But a question should be asked and considered before the first blow is struck: Is it necessary?
The answer is "of course" for rockhounds paying to dig in a quarry. The same is true for researchers with all their permits in order. Just proceed with the hammers, safely, and do no more damage than necessary.
The people on my 2005 field trip were not either, and we did not need to touch the outcrop in the first place.
Rockhounds are paying to indulge their desire, and researchers are working to advance science. But amateurs and other informal geologizers like myself are just pursuing a hobby. That is a lesser justification, but it's also one that lets us consider other values. I suggest that we play our game with this rule: Do hammering last, and only after explicitly deciding it's necessary.
The system I try to practice is this: Start by examining the rock from a distance, then from close up. That allows me to observe structural features and then study the details with that information in mind. The untouched rock may show both weathered and fresh surfaces, both of which are worth observing. For the closest look at the rock, I can then either lean in with my magnifier or pick up a piece from the ground. After that, if I decide I need to take away a piece, I'll look for one on the ground before taking one carefully from the outcrop. In my game, breaking off a piece of the outcrop just to stare at it and toss it away is a losing move.
Remember the two purposes of hammering: to make a fresh surface and to collect a sample. If those things are possible without touching the outcrop, everyone wins. Because against a hammer, the rocks don't stand a chance.