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Discussion Starter · #1 ·
I was wondering if anyone knows anything about good spots to collect rocks around Portland?

I'd love to find some volcanic rocks for Iwagumi similar to the Ryuo or Seiryu-seki. I'm sure we must have these in abundance given the make-up of the cascade and coastal mountains. I figured I'd just start keeping an eye out on hikes in the Columbia Gorge and on Mt. Hood.

I was also trying to figure out if there's anything I should keep in mind as far as mineral's and how it could effect the water in the aquarium. I figured I'd boil whatever I found and maybe leave it soaking in water for a week or so but beyond that are there rock types I should avoid?
 

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Most of the rock around here is basalt, which is dark and rather blocky. There are some cinders as well. You might be better off looking at some of the flood deposits from the Bret's Floods in the Willamette Valley as they're going to have rocks from outside this region. I'm not sure what type of rock Ryuo and Seiryu-seki are, perhaps rhyolite? The Rattlesnake Formation that is found in the Madras area is rather nice looking rhyolite, I even found some 'lilypad' (red rock similar to jasper with "bubbles" of green jasper or agate that looks like lilypads when sliced) in a quarry near Madras. (the quarry is on private property, so I can't tell you where it is, sorry) That rock tends to be a nice red color which I like, but is not traditional Iwagumi.

Probably the best place locally to look for rock is in the Columbia Gorge, along the cliff faces and road cuts.

If someone here can't give you a better answer I would probably call the Rice Museum, or better yet visit in person with a good clear picture of some Iwagumi rock (or better yet, a sample of it if you have some). If anyone knows about the local rock formations, it would be them. You might even find what you are looking for in the rock pile they have out front for kids to dig through!

http://www.ricenorthwestmuseum.org/
 

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Discussion Starter · #3 ·
Most of the rock around here is basalt, which is dark and rather blocky. There are some cinders as well. You might be better off looking at some of the flood deposits from the Bret's Floods in the Willamette Valley as they're going to have rocks from outside this region. I'm not sure what type of rock Ryuo and Seiryu-seki are, perhaps rhyolite? The Rattlesnake Formation that is found in the Madras area is rather nice looking rhyolite, I even found some 'lilypad' (red rock similar to jasper with "bubbles" of green jasper or agate that looks like lilypads when sliced) in a quarry near Madras. (the quarry is on private property, so I can't tell you where it is, sorry) That rock tends to be a nice red color which I like, but is not traditional Iwagumi.

Probably the best place locally to look for rock is in the Columbia Gorge, along the cliff faces and road cuts.

If someone here can't give you a better answer I would probably call the Rice Museum, or better yet visit in person with a good clear picture of some Iwagumi rock (or better yet, a sample of it if you have some). If anyone knows about the local rock formations, it would be them. You might even find what you are looking for in the rock pile they have out front for kids to dig through!

http://www.ricenorthwestmuseum.org/
Wow, I work literally 10 minutes down Hwy-26 from there and have lived in and around Portland my whole life and this is the first I'd ever heard of that place. Sounds pretty rad, I'll definitely have to check it out!

Thanks for the heads-up! For now I think I'm going to start off using some dark basalt rocks with white granite veins running through them that my friend found at the coast. I've had them soaking in water for a week now and I need to test the water for hardness to see if they're going work alright. I also boiled them for about an hour prior to soaking them so hopefully there won't be any issue with using them.
 

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Glad to be of help! It's a neat museum, truly world-class. They recently had a fossil fest that featured three fossil whales, although I don't think they are currently on display. My dad does a lot of volunteer work for them.

FYI, granite doesn't form veins in basalt, they are formed by two different processes. Basalt erupts and flows on the surface, cooling quickly so it has very small crystals in it, granite solidifies slowly under ground which is why it has large crystals in it. (they are also formed from different types of magma, but I won't get into that because it's boring. Basalt has more silicate in it than granite though)

The veins in the rock are probably quartz, which is made from silicate that had leached out of the rock into extremely hot water (superheated, basically) and crystallized as it cooled in cracks in the basalt. Silicate is what aquarium sand for fresh water aquariums is usually made from, so it is a very safe rock for aquariums. However, there are some other minerals that also form crystals under similar circumstances that are not so safe, so testing is still important.

My father is a rockhound, can't you tell? :D
 
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