(Team Design) Personal Development: the Rock Tumbler

Kent Dahlgren
4 min readSep 8, 2020

My grandparents had a little old rock polisher, which would run day and night for weeks beneath a back porch which served as the less-formal but more commonly-used entrance into their home, leading directly into their well-loved kitchen.

And some of my favorite memories (beyond those of my grandma Ruth’s delicious blackberry pies) include walking hand-in-hand at a child’s unhurried pace, listening to my granddad as he carefully taught me how to pick ordinary stones for inclusion within the next batch.

I’d sit in restless anticipation on that back porch, rocking on my heels as I listened to the tumbler grind and grind beneath my feet, trying to imagine how the stones might look and feel after being transformed from something rough and dull into treasures that were glassy-smooth and jewel-like in their near-perfection.

Not far from their home in Astoria, Oregon is a place called Agate Beach, which lies at the selvage of land and sea, where a uniquely-diverse variety of rock intersects with the Pacific Ocean’s ceaseless violence.

Those with rare local knowledge of the place will recognize with fondness what I’m about to share:

Those walking this beach are treated to countless polished stones, most of them translucent in such a manner that illuminates beautifully when held to the sun.

Their beauty sparkles and winks from the beach as you pass, but they were not created for you.

How are they polished?

The ocean carries unthinkable power from half-way across the globe, and over millennia the Pacific’s power pounds vast quantities of stone into rubble.

By degrees, smaller stones of equal hardness grind against each other, using the fine sand as a form of polishing aggregate.

Day and night, for millennia, stones that boast a lower quality of hardness are ground into sand, which the ocean carries away.

It’s simple!

So it was when we’d walk, carefully selecting rocks for the next batch in my grandparents’ rock polisher.

My granddad Henry carried to his final days a childlike fascination of the world’s countless novelties, and from this deep well of interest would coach me to select stones that were not too rough and of the proper shape.

He was a very tall man, a guy who carried a Browning Automatic at 17 into North Africa during World War II, who was later a logger in the forests of the Pacific Northwest, bent nearly in half decades later, hand-in-hand with his grandson explaining with great, unhurried patience how to select the perfect stone from a landscape of ordinary road gravel.

He’d explain that while one stone might be of equal hardness, it was not likely its rigid edge would do much beyond breaking the other stones into bits, and would thus emerge from the polisher about as dull as when it was originally picked.

In a sense: a single rough and hard stone emerges victorious in a contest with no actual victors.

Because, again: the stones polish themselves as they batter against others, without being pulverized, because they are of equal hardness.

This is kind of like the “iron sharpens iron” parable from the Bible, if you are so inclined, or in the spirit of the Two Row Wampum, as I’ve been learning from Sha’tekayenton and Kevin Guyan.

It’s not to suggest that the rejected stones did not have merit; their rigid edges are ideally-suited to act as a natural chisel as they tumble, cleaving other stone as it passes.

Some might argue that these rougher and sharper stones played a vital role in preparing the smaller and more round stones being chosen to be polished.

That sounds about right, but their contribution occurs far prior to the readiness to be added to the polisher, and are therefore rejected.

The stones chosen for the tumbler were those that had already been battered into a relatively round shape, because this is the important part of the story:

The reason one might invest in a rock tumbler isn’t for hopes that one stone emerges victorious, because that’s ridiculous.

Again, in order for a single stone to emerge “victorious,” it would have to be both harder than the others, and boast rougher edges, such that it batters the other rocks into dust.

That’s not victory.

The stone that “wins” isn’t polished as a result, because it was never afforded the benefit of having its ass kicked by other stones of equal hardness in the first place.


I’d argue that the value of the rock polisher isn’t in the many stones that emerge with a glassy-smooth, polished surface.

Sure, those rocks are pretty, but: I’d argue that the value of the rock polisher is metaphoric.

In order for the stones to be transformed from dull roughness into a polished state, they needed to be picked by someone with some knowledge of stone, and some wisdom about how the quality of hardness and violence is required to create something of such beauty.

The beauty of the stone is made possible because they are left to tumble for days and weeks, because you can’t keep checking in, can you?

And the beauty of the stones is made possible because they polish one another in great turbulence, or as I like to say:

“The rocks come out of the tumbler really pretty, but I’m pretty sure the experience itself sucks from the perspective of the rocks.”



Kent Dahlgren

Product management fix-it guy. World-famous people skills. Extremely small hands. (edit) marketing lady says I’m also supposed to say “CEO of software company”