Mouth of Knife River at Lake Superior

LOCATION: Knife River, MN

This trek commenced on a Sunday that was bright and cold. I could hardly contain my excitement to comb the rocky shoreline of Lake Superior. This would be the last nature outing I could do for a while as I was scheduled for hip replacement surgery the next week. (Left hip – that’s key.)

When there was a break in the post-brunch chatter, I beckoned my travel mates to hit the trails. Several “Me”s could be heard throughout the house. (Participation trophies all around!) Although, some were good enough to keep the home fires burning…

For our Sunday adventure, we went rockhounding near the water not far from a campground and the Knife River Marina Beach. Boulders, small stones and all kinds of natural matter were readily available at the surface, so no need for deep digging. We brought just our sacks and pockets. And we were appropriately dressed for the cold weather, including hats and boots.

Ann, Leslie, Peggy, and I headed out to the Lake Superior shoreline. Over time, the tides had pushed up a lot of debris, creating berms of sediment, stone, wood, and remnants that had to be scaled over before getting to the pebbled beach. Sturdy footwear with grip soles was helpful here.

We triumphantly marched over the berms towards our hallowed destination – the water. Despite our solid start, it was clear that others had beaten us to the mark

WHOA!

I’m no master tracker, so it was hard to say how fresh those tracks were. But it was certainly a time when I was glad to be in the company of friends.

All eyes swerved around, up and down, to make sure we were sans bear or beast.

Seeing none we proceeded along the shore observing the wonderful treasures beneath our feet. There were rocks of all shapes and colors, driftwood, sea glass and shells. Glorious stuff. Being able to wet the rocks to see the patterns and colors pop out enriched the experience. We did do some surface digging with our hands, but the sand was so cold we had to get in and out quickly.

It was great fun sharing our finds along the way. Our voices rang out from all along the beach:

“Look at this!”
“What is this?”
“How beautiful is this one!?!”
“Whoa!”

The only thing better than making a discovery is sharing that discovery. No matter how large or small the find, the moment of discovery in the midst of friends is magic. This is a priceless moment in my head and heart: exploring together.

We began to fill our sacks and continued walking along the shoreline. After some distance, we came to a most beautiful sight – the mouth of the Knife River. It was burbling into Lake Superior, creating an idyllic scene. The sound of the dancing water again silenced our conversations.

Side Note: Whenever I stand at the point where two bodies of water meet, I often think about what that merge is like. In this case I wonder, “Do the river dwellers go willingly into the lake? Is it a harmonious hookup – something spiritual? Is the lake life community welcoming the river folk with open fins and cheering gills?”

Maybe some life forms splash forward with glee, while others resist the osmotic blend in a “Hell no! We won’t go!” kind of way. And what about freshwater bodies merging with saltwater bodies? What kind of craziness is that?!?

After some rudimentary research (remember, I’m a student, not an earth sciences expert), I discovered that:

When a river flows into a freshwater lake, a freshwater estuary is created. Freshwater estuaries are semi-enclosed areas where the waters of the river and lake mix.
Although freshwater estuaries are not brackish (fresh water mixed with salt water), the chemical composition of the river and lake water is different. River water is warmer and less dense than lake water.
The mixing of the two freshwater systems contributes to lake turnover, which is the mixing of the waters of a lake.
Freshwater estuaries provide many of the same ecosystem services and functions as brackish estuaries, such as serving as natural filters for runoff and providing nursery grounds for many species of birds, fish, and other animals.

That is a good start to answering the questions. If you know more, feel free to drop a note in the comments. Otherwise, we’ll discuss this in detail in a future blog.

As it went, the wind and weather were much colder than on previous treks, and we didn’t have the luxury of forest coverage. After a good chunk of time in the bluster, a couple of folks wanted to turn around and head back. “Wimps,” I thought to myself.

Ann indicated she would stay out a little longer with me. She was so thoughtful. “Oh, Ann. It’s fine. You can head back, too,” I said. I’ll be behind you shortly.” Wisely (and because she knows my wayward ways), Ann stayed for the duration. “I just want to go a bit further up the river,” I yelled back. “There’s a ton of rocks over there.”

Apparently not satisfied with the wonderful haul already in my red sack and the awesome moments shared with friends, I needed to experience even more. I ventured around the point to go up the river, rationalizing that I may find another Lake Superior Agate or gem.

No sooner had I come to the other side of the point when I saw ice already on the shoreline. Hunh. The water was obviously a tad cooler than I thought.

Undaunted by the ice and seeing so many rocks, I raced excitedly toward the water’s edge. But my excitement turned to uh-ohhh when my feet tried to settle on literally thousands of smooth, loose stones burnished by the elements. Like aged undergarments, the slick rocks slid away rather than supported my body. Zero ‘lift and separate’ or traction.

Realizing I was on completely unstable ground, I slowly turned my right boot to move back to more solid land. So far, so good. Next, I mightily pushed off with my left foot to thrust me forward. Alas, there was no solid ground to thrust from. My left boot vanished into the parting stones like a log in quicksand. Finally, the whole left side of my body – the future surgery side – fell toward the rocks and water. Like a breaching humpback, my whole body arched and took a dip. WTF!?!?!?!?

As I recall, what happened next went in this order:

The water was so cold I lost my breath for a few seconds
I looked around to make sure no one had witnessed this unforgivable hiking faux pas
I finally caught a glimpse of Ann, who was rockhounding with fervor and completely unaware of my breach (which made me love her even more – because she loves rocks!)
That, in turn, made me start laughing and I could barely call for help between my chortles.
Somewhere along the way Ann heard me and came running!
(The ~~wimps~~ wise ones who’d left earlier came running back too.)
I held up my hand like a third base coach to stop Ann from suffering the same humiliating collapse I’d just experienced.
Ann waved me off and rounded third for home. She wholeheartedly and unselfishly reached in to help me get up.
I grabbed her hand and crawled out of the water like a soaked weasel. Pathetic.

After finally getting upright, I asked the wise ones to take pictures to capture Ann’s heroics and my dumbfuckery.

Smooth. Consider this a good example of a bad example!

WHAT’D WE LEARN?

Anyone who has a pending surgery shouldn’t do what I did! Seriously, don’t go on escapades or challenge yourself to a ‘last hurrah’ because you still feel like you’re 20-something. The end result of my slippage was some big-time bruising that nearly postponed my surgery. Not worth it.
Going forward I’ll try to be more cognizant of when I have plenty in my sack, in my closet, in my fridge, in my world. ‘More’ is not needed.

Overall, the good news is that everyone survived relatively intact and we got some great mementos and memories from our adventures. Thank you, Ann, Peggy and Leslie!

So what kind of goodies did we gather?

FINDINGS

The options were endless. Here’s some from our cache:

We picked up a good variety, including basalt, gneiss, rhyolite, jasper, brecciated jasper and Lake Superior agates.

Lake Superior Agate is the state gem of Minnesota and is a favorite find of many rock hounds. Let’s explore it further.

Lake Superior Agate

Colors: Reddish, rust, orange, brown, yellow, blue (rare); banding in gray, white, black
Uses: Jewelry, decoration, slices, displays
Hardness: Generally 6.5-7 on the Mohs scale of 1-10 (relatively hard and usable for jewelry)
Luster: Waxy

What distinguishes Lake Superior Agates from other agates is their color and structure. The red/rust/brown and yellow hues that characterize most of these agates are caused by the oxidation of iron from the rich iron mineral deposits in the region. Those iron minerals – via groundwater – were trapped in gas bubbles in lava flows generated over a billion years ago.

The rock was widely distributed beyond Lake Superior’s shores (northeastern and central Minnesota and northwestern Wisconsin). The Minnesota DNR website sums up the ‘agatizing’ process nicely:

“Water vapor and carbon dioxide became trapped within the solidified [lava] flows in the form of millions of bubbles, called gas pockets or vesicles. Later, groundwater carrying ferric iron, quartz, and other dissolved minerals passed through the trapped gas vesicles. These quartz-rich groundwater solutions crystallized into concentric bands of fine-grained quartz called chalcedony…”

Again, this all happened between 10,000-20,000 years ago during the Wisconsin glaciation we learned about in earlier blogs. See how it’s all tying together!?!
Ahhh, earth sciences.

The pressure and movement during the last glacial age caused many agates to break free from the lava rock to become standalone specimens that are actually stronger than the volcanic rock that housed them.

Another spectacular feature of Lake Superior Agates is their distinctive banding patterns. They appear in layers and concentric circles similar to tree rings. Some also have ‘eyes’ or ‘tubes.’ The rarest form is a blue agate, a cobalt blue stone that can be mistaken for other types of rock.

Today rock collectors can still find some of these agates embedded in the original ‘host’ rocks. As luck would have it, I found one on our recent trek: 1” x 1” agate in basalt.

Appearance and Formation:
- Lake Superior Agates are typically shaped as irregular spheres.
- They are comprised of quartz, often reddened by iron deposited in layers
- These agates range in size from pea-sized to 20 pounds; larger samples are extremely rare.
- Unpolished stones display shades of red, orange, and yellow, with the banding breaking the surface.
Polished Beauty:
- When polished, Lake Superior Agates take on a high shine, displaying exceptional color and intricate banding.
- The reds can range from bright to dull, sometimes resembling rusty hues.
- Some specimens even reveal quartz centers
Blue Lake Superior Agate:
- The most sought-after variety contains shades of cobalt blue, making it rare.
- While some nodules have small patches of blue, occasionally you’ll find a solid blue nodule with banding.

Lake Superior agates can be left rough or polished. They are generally used for jewelry, decorations and displayed in collections. The larger agates are often sawn into slices to fully display the rich colors and patterns.

Brecciated Jasper (brec ci ate)

Note the white and clear fragments of quartz and other minerals in the brecciated jaspers above.

Brecciated Jasper is another eye-catching gemstone with unique features that make it stand out. Rock shops will often have tumbled samples of brecciated jaspers.

Here are some key points about its structure and characteristics:

Texture:
- Its unique texture appears to be that of angular fragments of minerals or rocks cemented together within the stone.
- This fragmented appearance can resemble mosaic or stained glass and adds to its visual appeal.

Color:
- Brecciated Jasper comes in a variety of colors, with red, brown, beige, and yellow being the most common hues.
- The presence of iron compounds, common to this region, gives it its deep red tones.
- Some specimens contain white or clear crystal inclusions visible between the angular fragments.
Patterns:
- Brecciated Jasper may also exhibit intricate patterns and banding resulting from the arrangement of different mineral fragments within the stone.
Composition:
- Brecciated Jasper is primarily composed of silicon dioxide (SiO2), like all forms of quartz.
- It also contains other minerals that contribute to its distinctive look.
- Its composition makes it valuable for jewelry making, decorative objects, and lapidary work.

Gneiss (prouncedˈnīs )

Colors: Yellow, gray, white
Uses: Construction, agriculture, and environmental projects. Often crushed.
Hardness: Generally 2-3 on the Mohs scale of 1-10 (meaning limestone is fairly soft)

Gneiss is a fascinating metamorphic rock with distinct features that make it appealing both visually and scientifically.

Formation and Composition:

Gneiss forms through high-temperature and high-pressure metamorphism acting on pre-existing rocks, which can be either igneous or sedimentary.
It typically develops at higher temperatures and pressures than schist.
The minerals in gneiss may come from rocks that were originally either igneous or sedimentary. These rocks were heated, squeezed, and their minerals recrystallized.

Banded Texture:
- Gneiss nearly always displays a banded texture, characterized by alternating darker and lighter colored bands.
- The bands result from the arrangement of different mineral grains within the rock.
Layering and Bands:
- Gneiss is common in the ancient crust of continental shields.
- Some of the oldest rocks on Earth are gneisses, such as the Acasta Gneiss.
- The layers or bands in gneiss are compositional, meaning they have varying concentrations of minerals.
- Darker bands contain more mafic minerals (rich in magnesium and iron), while lighter bands contain more felsic minerals (silicate minerals with lighter elements like silicon, oxygen, aluminum, sodium, and potassium).
Texture and Appearance:
- Gneiss is coarse-grained, with mineral grains visible to the naked eye.
- It forms obvious compositional layers, but its tendency to fracture along these layers is weak.
- The rock may be rough to the touch.
Varieties and Names:
- Gneisses can be named after specific components, such as garnet gneiss, biotite gneiss, or albite gneiss.
- Orthogneiss comes from an igneous rock source, while paragneiss originates from a sedimentary rock.
- The term gneissose describes rocks with the texture of gneiss.
Well, THAT was an invigorating trek! Along with our journey, we had some incredible discoveries to look at, feel and appreciate. We decided to take home our ‘prizes’ and see what we’re inspired to create.

WHAT D’YA MAKE OF IT?

We experienced a virtual river of finds.

While they’re all beautiful, I decided to work with the state gem, Lake Superior Agate, and possibly some jasper.

Working in sterling silver I wanted to create a clean, flowing setting to complement a Lake Superior agate cabochon I’d purchased.

After sawing the backplate, I cut and soldered the bezel, then set the stone:

Rather than soldering on a bail, I left space on the backplate and bezel to drill a hole for a large jump ring That allows for the pendant to be attached to various types of necklaces and chains:

1. Freshwater pearls, 2) Red jasper and silver chain, 3) Layered with other pendants

Ultimately, the gray bands in the agate called for some iridescent pearls including some beautiful blue-gray potato pearls that mimic the moody color of Lake Superior on brisk days.

Oh, and a matching pair of earrings completes the look.

And there you have it for this blog.

If you’d like your own one-of-a-kind agate, jasper or other gem memento, please reach out to me at Nancy@skinoftheearth.com

COMING UP – We’ll head east to experience the natural grandeur of Maine’s coastal geography and some hiking trail wonders in ‘Schist and Giggles.’