Behold, staurolite
Winter setting into the mountains above Big Carpenter Creek, where staurolite, a mineral that forms unique shapes, is plentiful. (Photos by JASON WILMOTH)
Staurolite cross found at Big Carpenter Creek.
Staurolite forms various shapes of crosses.
Garnets at a boulder at Big Carpenter Creek.
Panning for “crosses” in North Idaho
By JASON WILMOTH
Coeur Voice Writer
As the snow starts to creep down the mountain tops to the valleys below, I start feeling a little frantic. We never accomplish all the adventures we had planned for the season, and with the mountains beginning to close off, restricting us to the lowlands.
Access becomes the main factor in planning any adventure.
I’ve learned over the years how to push further into the winter mountains, but there always comes a point when there’s just too much snow. Until that point comes, though, there are still some places to go. Big Carpenter Creek is one of them.
I initially explored Big Carpenter Creek by accident. I was trying to get to Emerald Creek to dig for star garnets with my daughters. I looked at the map the night before, but then forgot it the following morning. With only a general idea of where to go, we chanced a road out of Fernwood which I thought went the right way and ended up on Big Carpenter Creek instead, one drainage north of Emerald Creek.
With star garnets in mind, we continued the search for Emerald Creek and eventually found the dig site, late, after taking the long way to get there. We washed buckets of clay, alongside a crowd of people, in the sluice operated by the U.S. Forest Service.
We brought home a few dime-sized garnets that day. I showed my wife the bounty from our afternoon’s work.
“Meh,” she said.
Rough garnets aren’t much to look at. They require shaping and polishing to show their beauty. The garnets on display at the rangers’ shack are enough to keep you eager, and the stories about the fist-sized garnet found the week before made it difficult to give up, but we decided that next time we would go on a rainy day in the middle of the week, when the crowd of people would stay home.
When I looked at the map that evening, I found that there was a mineral called staurolite in the rock outcroppings on Big Carpenter Creek, and after some more research, I was interested in exploring more. Even better, I already knew how to get there, so I logged it in the grey matter toward the back of my brain, under “places to check out”.
The next time we found ourselves at Big Carpenter Creek, it was again the fault of the guy that brought everything except the map. We were looking for a rockhounding location east of Moscow, but after realizing I had missed an important turn, we decided to head for Big Carpenter Creek instead. With a little more knowledge in hand, we were able to find some chunks of staurolite, and on subsequent visits we have found some great crosses. South of Lake Coeur d’Alene, the mountains have led a tortured past. Driving past St. Maries, you pass road cuts of pillow basalt, formed as lava cooled underwater.
Then, further south, there are sparkling mica-filled rocks with quartz veins running across them at sharp angles. The metamorphic rocks in the area around Fernwood were formed from clays that were pushed deep into the earth where they heated to just the right temperature and pressure for minerals in the clay to separate out and reform.
Staurolite forms by the same geologic process that produces garnets, but the iron-aluminum-silicate-hydroxide mineral coagulates out of the parent rock at a slightly higher temperature than garnet does.
The presence of staurolite in metamorphic rock is used as an indicator of the temperatures and pressures the rock has been subjected to.
The really cool part about staurolite, however, is that it often forms “crosses.”
My wife was unimpressed by the garnets I brought home, but her response to the staurolite crosses was, “Wow! That’s crazy how they form like that!”.
Big Carpenter Creek flows just one drainage north of Emerald Creek, out of the same mountains. The north side of the mountains are interspersed with Potlatch Corporation timber lands, state and private lands. The road is well-used in the winter and stays in the valley bottom until just after the staurolite site. As such, it’s an excellent late winter/early spring rockhounding spot, but once spring runoff begins, it will be difficult to pan the creek gravels until the water subsides in summer.
I usually park on Potlatch land and hike the creek.
Staurolite has a higher specific gravity than the surrounding gravel, and much like garnet, will be deep in the gravel. You need to buy a recreational permit to use Potlatch Corporation timber lands. They are available online and are good for the entire year.
Equipment
I usually take a home-built, quarter-inch box-screen, some shovels, a couple buckets and a gold pan. Be aware, I have seen both black bear and cougar prints in the mud and sand along the creek’s edge.
Logistics
Whether you are coming from Spokane or Coeur d’Alene, you will want to drive to St. Maries and head south on Highway 3.
Roughly 20 miles south, you will come to the town of Fernwood. Turn right onto Carpenter Creek road and cross the St. Maries River. Continue along Carpenter Creek road about two miles from Fernwood, making sure you don’t turn right onto Little Carpenter Creek Road which you will pass first. Veer right at the old wooden cattle chute. About four potholed miles up the valley you will come to a left-hand switchback that heads immediately uphill. The rock outcropping tucked into the switchback is full of staurolite, and you can pan the creek to your right.
If you aren’t too late when you go, the larch trees on the mountains above the creek will still be brilliant, and a short drive up the road past the dig site will provide you with some amazing views.