Beach Stones

“The insolent quietness of stones”

                                                                (R. Jeffers)

Rocks, petrified fossils and seabeans found along the Pacific NW Coast

While I wouldn’t consider myself a “rockhound” (one who is devoted to the collection of stones/rocks), I do love beachcombing for specific types of stones because of their color or texture or solidity or simply, because of their “insolent quietness.”

Some rocks are worlds unto themselves

I love collecting Beach Stones. Or Beach Rocks. Or both!  Wait! Is there even a difference or is it all semantics? Well, the common consensus among geologists is that there are some differences between the terms. ‘Stones’ (and pebbles) are restricted to smaller material. And stones are often fashioned into tools by humans. Hence, stone implies some sort of human use or small size. A ‘stone’s throw’, for instance, connotes something nearby. “Beach stones” are generally rocks one can pocket while beachcombing.

Although the term ‘rock’ can also be used in these situations, rocks can also be considered much, much bigger than stones. For instance, if a boulder falls down a mountainside, no one says, “Wow! That’s a big stone!”  Or if a stone falls down a hillside and lands on your car windshield — then the rock does the same thing, which do you assume would do more damage? I’m banking on the rock.

So, in essence, geologists tend to regard all stones (and pebbles) as rocks but not all rocks as stones or pebbles.  Got that?

Rock or stone, who cares? Let’s learn more about these wonderful beach treasures to aid you in your beachcomb I.D. forays.

A selection of rocks found along the coast of the Pacific Northwest, (as well as some sea beans)

The Earth’s crust is made of materials called rocks, some of which were formed 3.8 billion years ago. Rocks are made up of natural chemical substances called minerals. Some rocks contain only one mineral, such as marble, but most rocks contain crystals of several different minerals. Some of these minerals contain metals such as gold, iron and aluminum. Others hold prized gemstones (diamonds, rubies), or fossil fuels that produce energy (coal) or granite and sandstone people use to build structures.

There are three main types of rocks, and each one is produced in different ways. Sedimentary rocks (chalk, limestone, clay, shale, sandstone) cover 75% of the earth’s surface and involve the process of deposition, where fine rock particles have been worn away, grain by grain, layer by layer until they are eventually carried and deposited into oceans and lakes via by the wind, rivers or glaciers. Once there, the tiny fragments are compressed (squashed) and cemented together, which forms sedimentary rock.

Metamorphic rocks (like marble, slate) form when great pressure and/or heat – through volcanic eruptions or shifting tectonic plates – greatly altering the minerals already existing in primary underground rocks, so that these rocks transform into another kind of rock.

Basalt brimstones from Brimstone Island, Maine

Igneous rocks (granite, basalt) are created when magma (molten rock) rises from deep underground, cools and solidifies at or near the Earth’s surface. Erosive forces sculpt their current forms.

Minerals are the building blocks of rocks. There are more than 3000 known minerals (the number is still growing), but of these only about 20 minerals are very common, and of these, only 9 constitute 95% of the earth’s crust. These 9 minerals are all silicates, and can be subdivided into the following groups:

Olivine minerals found on Hawaii’s Big Island

Mafic Minerals:  The term mafic is used for silicate minerals, magmas, and rocks that are relatively high in the heavier elements such as iron and magnesium. Some of these minerals include mica, feldspar, and olivine (which can be found on the Big Island).

Mafic rocks, like basalt, are overall of dark color though some are dark greenish ranging up to light and transparent.  Older basalt rocks are especially abundant on the Maine and Washington coastlines. Newer basalt is abundant on volcanic islands such as those found in the Hawaii’s chain.

Cryptocrystalline and crystaline quartz from Chesapeake Bay Region

Felsic Minerals:

Felsic is a term used for silicate minerals, magmas and rocks which have a lower percentage of the heavier elements, and are correspondingly enriched in the lighter elements, such as silica and oxygen, aluminum and potassium. Felsic minerals include mica, feldspar and quartz. All of these minerals form through crystallization from silicate melts in the crust and mantle. Because Felsic minerals are light in color, felsic rocks are also typically of light color.

I love the way some beach stones feel. Soothing.  Solid. Impenetrable. And I value my favorite beach stones (or rocks) as much as I do my other special beach treasures.

In fact, I carry one beach stone with me everywhere. It is a large orb of flat smooth quartz. And when it sits in the palm of my hand and my fingers smooth over it, it calms me down and/or comforts me.  I am particularly drawn to both rose quartz and basalt brimstone, Oregon ocean agates and fossil corals that have turned to stone such as those found along Calvert Cliffs, MD. and Petoskey, MI.

Beautiful polished petrified wood

Petrified wood, Washington State’s gemstone, is another beautiful rock and I went gaga pouring over the stony beaches of the San Juan islands where the rock colors stream down the color wheel spectrum from cream to yellow, to every shade of green, purple and red. I had never seen anything like it.  More info…

For beachcombers who favor sea glass, don’t brush beach stones off too quickly. Know this: sea glass is largely composed of silica, much like quartz. Over millions of years, quartz breaks down into smaller rocks and then stones, some of which (the crystalline) are transparent and resemble sea glass (these specimens are often referred to as “Cape May Diamonds” because so many are found on beaches there).

Magnificent, soothing rose quartz

As time and weather further break down quartz stones, they transform into small grains of sand. Beaches worldwide are composed of quartz sand. And if you heat quartz sand to 4200 degrees, it melts and transforms into glass (called ‘fulgurite’).

The circle of life. Or rock. Or stone. Or glass. Some of which rest in our pockets, to take home and treasure. To learn more, here is a good reference site for rock hounds:


8 thoughts on “Beach Stones

  1. Great post. Who does not collect a piece of place.
    Aging these things is what I’m after…it seems insane to generally throw them into the vast bucket of 40 million to 3 billion. But perhaps that is all we have? Do let me know you idea! Am writing a simplistic poem because I think we all forget that our small collections will still be around when the world is not.
    Again thanks.

    1. Perhaps. I can’t tell you the number of people I meet who can
      t remember where their childhood beachcomb treasures disappeared to! (Am thinking the landfill, sadly…)

  2. Hello Dr. Beachcomb! My father is a prolific beachcomber, and I am searching for an answer for him. While beachcombing he has noticed a prevalence of rocks in the shape of flat ellipses. He has collected buckets of these similarly shaped ellipses. What creates this shape? Is it the waves? The wind? I really want to get to the bottom of this.

    I hope you can help! Thank you!

    1. Yes, I found a lot of my favorite quartz ellipses on Chesapeake Bay beaches and I have no idea why this is so – particularly because on beaches just 1.5 hrs away the quart stones are very different. Lumpier. Rounded. Is it low impact wave wash over millions of years? A geologist might know.

  3. Hi! This is Jundel Cabuyao. I totally admire your article. I also like stones coming from the beach. I already found agates, petrified wood, chalk turquoise, flint quartz, chrysocolla, fossil stones, jaspers. I am still classifying each of them because they came from different types. there are too much from. I wish I could make a website like this so that I can share some pictures.
    Thumbs up for you!!

    1. Hi Jundel – well, not quite a year late in replying (never knew I could do this – or rather, never paid attention before!) Your collection sounds lovely and varied. And I agree about beach stones. I think they are totally underappreciated. I carry one very dense, smooth piece of glacial til with me on all my travels. And my favorite beach treasure of all time is a very large flat smooth orb of rose quartz. I’d be happy to post some of your pictures sometime on my Facebook page.

  4. Hello, thanks for this great information. Your article helped me identify a pretty little basalt brimstone that I have and have always enjoyed holding. The one I have is very smooth to the touch, but not quite glassy like a polished stone. I’m curious, how many years does it take basalt to erode into a nice smooth stone?

    1. LOVE brimstone but osh, I really have no clue as to the aging process of basalt though the basalt on the Big island is rarely polished or smooth (too new, I guess) yet on some Pacific North West beaches I know it can be very worn.

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