Last Note From Plymouth: Siderite Sighting?

This odd looking lump is on my friend’s horse ranch on Carbondale Road, outside of Plymouth, California in rural Amador County. Near the center of California’s Mother Lode Country. I wrote about this place in a previous post. The soil is nondescript, red foothill clay, with the most common rock underfoot being broken pieces of iron stained quartz.

And then there is this thing, which my first guess was a bunch of leftover concrete that someone had attempted to color. Perhaps they dumped out their concrete mixer at this spot? There is no sign of any unusual concrete work in the area, but who knows? I did not have my rock hammer as I was traveling and renting a vehicle.

Usually concrete aggregate has much smaller stones than the blobs we see here. I am up to any guesses. There is a creek nearby with what I presume are rounded stones but it is not on my friend’s property so I haven’t checked it out. I can’t imagine anyone making their own concrete with locally collected rock, think of the work, but I suppose it is possible.

Another possibility is siderite, which Mindat.org lists as being in the general area. A nice man named Brice on the Facebook group, Rocks and Minerals – identification and information, made this suggestion.

Siderite is an iron mineral, of which I am only now reading about. Apparently, siderite is valuable mineral in theory since it contains a high amount of iron, possibly 48%. In such a small outcropping it is totally uneconomic but an interesting curiosity to any rockhound or mineral collector walking the woods. Its presence may lead to the discovery of other nearby minerals such as manganese.

The odd looking lumps may be large siderite crystals that have weathered to their present shape over time. More on that below.

 

This is an overall view of what I will call for now, the outcropping. For a much larger picture to ponder over, click here. Or click on the photo itself.

 

Closeup photograph. Pen for scale.

 

A damaged or otherwise altered section of the outcropping. Broken concrete doesn’t turn black, it retains a whitish color due to the Portland cement. If the concrete were mixed with a colorant originally, however, in the drum, the color would run throughout the mix.  But you would have one color, and not two as in the photo. An iron ore deposit just might make sense. The outer layer has weathered and oxidized red, rusted if you will, while the more newly exposed material has yet to change.

 

The above picture is courtesy of Dennis Miller. Used with permission. It’s siderite from an area near Chihuahua, Mexico. Note the globular forms. I’m speculating that the globular material in the outcropping I came across are weathered, eroded permutations of this siderite’s original form. Or not.

The Henry Holt Guide to Minerals, Rocks, and Fossils (very British) says that siderite crystals can be, “[M]assive, fibrous, compact, botryoidal, or earthy.” The outcropping seen here is definitely botryoidal.

The book goes on to say that massive siderite is widespread in sedimentary rocks, however, this area is in the Sierra Nevada foothills, granite, quartz and slate country. Judging from my experience in nearby El Dorado County. There are notable, economic clay deposits several miles distant, which leads me to this quote from Holt’s book.

“Massive siderite is widespread in sedimentary rocks, particularly in clays and shales where it forms clay ironstones which are usually concretionary in origin.”

Concretionary. And an outcropping that looks like concrete. Iron stains every piece of broken quartz on the ground. So iron must be in the soil. Can anyone put this all together?

Mindat doesn’t show siderite as found in Amador County, however, these reports are usually confined to recording occurrences of economic value. Or a citation in the scientific literature. Like in a geology report. Not all outcroppings everywhere can possibly be recorded. Siderite has been reported in the county of El Dorado, immediately north, and Calaveras, immediately south. In the plant world, we would call an occurrence in a new area as a range extension. And you thought rocks and minerals had a peculiar vocabulary!

I am waiting on a local rock and gem club member to tell me what he thinks the outcropping is. And I will have a friend test the outcropping with a magnet. That may be diagnostic. Although I see on Mindat that siderite is paramagnetic, a new term for me. It essentially means weakly magnetic. I’ll mail my friend one of my rare-earth magnets. Maybe that will make a difference in testing. I’ll report back later. Thanks, again, Dennis, for the photograph.

Greetings From Plymouth, California

A few days ago I had to leave Las Vegas on an emergency trip to help out some friends. The couple I know owns a hundred acre horse ranch in Amador County, in the Sierra Nevada foothills. Their spread is near Plymouth. The heart of California’s Mother Lode Gold country.

When this husband and wife first bought their property I came out with my gold detector. I was delighted to find broken quartz everywhere. Most displayed iron staining and many contained vugs or cavities.

Alas, only a small speck or two of gold was found in a shallow ditch running through the acreage. The nearby creek had been dredged for gold but my friends didn’t own any of that stream. Nor did they own property containing any tailings.

Never-the-less, the many small pieces present might be useful one day for tumbling, as their dark vein patterns contrast nicely with the quartz matrix or host rock. Even if you can’t find gold, you can often find something else.

Iron staining and vugs are signs of mineralization and activity within a rock. Something has acted on the stone. Most quartz is barren, white colored with no character. Sometimes called bull quartz. You look for character when you look for gold. Decomposition or crumbling quartz is another sign to watch for.

Having said all this, the finest gold in quartz I have found displays no other minerals save a scattering of the gold itself. My specimens are milky to near pure white with only gold showing in the matrix.

The lesson is that if you have the time, detect all quartz, even that which looks sterile. If you don’t have the time, limit your search to quartz that shows mineralization or the effects of forces which have altered the rock.


 

The quartz on the left shows iron staining, the material on the right shows vugs. These have not been cleaned and both show the clay soil of the area.


 

The larger rock might make one or two interesting slabs. The smaller pieces might be tumbled.

 

 

Latest Spot X Firmware Update Available

Time for all Spot X users to update their firmware. Let’s make certain you know how to do this.

1. Download the device updater  to your computer and then install it. Run the program. Do this first. THEN

2. Connect your Spot X and follow the instructions presented.

Again, download the latest version of the updater program first, then connect your device. DO NOT USE an old updater. You must download the newest updater first.

My device appears to be working well after the update.

This is what Spot X says in their latest e-mail:

In our continued effort to ensure the best possible SPOT X user experience, we have made some updates to the device firmware V1.7.14 and the device updater 1.12.8 to improve usability and overall intuitiveness. You need to first download the latest SPOT X device updater. Next, connect and update your SPOT X firmware to start benefiting from these upgrades on your next adventure. Below are some of the update highlights.

What Does an Agate Look Like?

Agates occur in nearly every state, along with countries around the world. Their patterns are endless and often striking, sometimes unbelievable. Right now there is a great agate thread going on on the open Facebook group Rockhound Connection:

https://www.facebook.com/groups/169785333057/

Make sure to check out the posts. They are all variations of quartz.

As beautiful as some of these cut and polished specimens are, many beginners are confused as to what to look for. Although not always present, a certain translucence and a wavy character to the rock are good signs. Some agates are so outrageously striped that there is no doubt as to what they are.

Here is a video of an agate that I liked so much that I have never had the heart to cut it open. The second photograph shows another agate from the same location, one I cut into a slab with a rock saw.

Both of these rocks are for examples only, they did not come from the Southwest. But if you are ever in Northern California, you may want to check the riverbed of Cache Creek in Yolo County. Good luck.

https://www.yolocounty.org/general-government/general-government-departments/parks/parks-information/camp-haswell

Uncut agate. Click on image or text link below. (Movie)

Cache_Creek_Agate_green

Cut agate:

Quartzsite is Here and The Fun Has Begun!

‎Neal Behnke‎ is writing daily reports to the Rockhound Connection on Facebook, a group worth following. Here’s Neal’s latest:

Welcome one and all to day 7 at the wonder in the desert, Quartzsite! Uncle Neal will stamp your passport and show you the door.

Quartzsite Arizona is really a rock hounds dream, established many years ago by wandering camel farmers, it has had a continuous rock show going since John Denver left and moved to Colorado and got all weird. First tourists started stopping as the freeway was slowly built, sometimes they would wander into the desert, sometimes they would wander back with rocks they would then sell to other tourists for water and trinkets. After 1978 the freeway reached almost a mile past town and the city was named.

Quartzsite is a fantastic place to rock hound, the local rock club (friends of Quartzsite) offer rock hounding trips, volunteer to clean the public bus benches and hand out cheese sandwiches. Please be aware if you are approached by anyone saying they will take you rockhounding, ask to see their cheese sandwich. Last year over a 100 rock hounds were tricked into looking for valley opal and 12 swimming pools were built. It is a good chance that if you are standing in someones back yard with a shovel and you are within 10 feet of wifi and a coffee maker, you are not rock hounding.

Todays Desert gardens events include Escape Room! held on the Lido deck, your goal is to try getting out of the house, finding the keys and your rock hammer and avoiding all your adult responsibilities so you can wander in the desert.

If you purchased any Cinnabar from Toxic Tonys minerals, please be aware that testing has confirmed that this particular material is hardly toxic at all, if you would like the high grade stuff please come back this morning.

Kids events today include buckskin Willys scorpion ranch! Willy has rustled up some 1.2 million desert red spotted viper scorpions, all in his .01 acre spread! Its fun to watch the little buggers tear across the desert floor, if you lean close over the 1 foot fence you can hear their tiny feet skittering in the sand!

Milking and stampede starts today at 1.

Support Mindat.org As They Reach For Their 2018 Goal

Update:

They reached their goal! Thanks to everyone for your support.

Original Post:

As they simply put it, “Mindat.org is the world’s largest open database of minerals, rocks, meteorites and the localities they come from.” It is one of the two or three most essential online resources for rockhounds and prospectors.

You can keep it free and open by giving a few dollars before year’s end. I sponsor their agate page and you can be a sponsor, too, of one of hundreds of available mineral pages. They are extremely close to meeting their fund raising goal. Please help.

https://www.mindat.org/

The Tonopah Historic Mining Park Part 1

The Tonopah Historic Mining Park Foundation has begun fund raising to physically secure what’s known as the Silver Top Headframe, one of three located at the Mining Park. A headframe is the signature feature of any large mine, permitting the hoisting of workers and ore from deep below to the top of the complex. A very few 2019 calendars, printed to help raise funds for the Foundation, are available at the Mining Park Visitor center for purchase.

While it may be winter, planning a park visit can start now by checking out its website or by reading up on Tonopah’s fabled mining history. Make sure to stop in if you’re heading to Quartzsite in January or Tucson in February. There are other reasons to go to Tonopah.

Anyone going to or leaving the Southwest by way of US 95 in Nevada should stop for many excellent reasons. The first is fuel, since the nearest gas stations are 100 miles north and south of town. After you’ve topped your tank, consider visiting the Central Nevada Museum in Tonopah, the city’s best kept secret. After that, stop by Whitney’s Bookshelf, right on 95, a fine used bookstore, often with excellent mining books. Hometown Pizza is across the street if you are hungry, usually serving pizza by the slice. If you’d like different fare, try the Pitman Cafe in the historic and period restored Mizpah Hotel. If you’re not in a rush to get out of town, think about getting a room at the Mizpah. I like the corner room on the fourth floor, the one with the claw foot bathtub. I think it is 409. But I digress. The best reason for any prospector or rockhound to stop in Tonopah is the Historic Mining Park, owned by the city and operated under regular, dependable hours.

Tonopah was America’s last great gold and silver strike. You’ve heard about the Gold Rush of 1849, the Comstock, and the Klondike. But there was also Tonopah in 1900 and for years thereafter. The visitor center and the the park grounds highlight this stupendous and spectacular hunt for precious metal at the turn of the century. The park is right behind the Mizpah Hotel. The entrance road is best approached in larger vehicles by Burro Street. The visitor center parking lot has room for two or three RVs and the exit road is a pull-through, so there is no worry about having to back up.

The grounds offer a self-guided tour. Pick up a map at the visitor center which also houses a terrific rock, gem, and mineral museum. As for the grounds, hiking the park at 6,000 feet can be tough at times but take it slow and take some water. Great opportunities for photographs. For those out of shape or mobility challenged, tours on a Polaris with a guide can be arranged. Call for current availability and charges.

As to the Foundation’s principal project, securing the Headframe, Eva La Rue, Administrative Assistant for the Tonopah Historic Mining Park Foundation, told me this story in an e-mail:

“Because the Foundation was created to basically help preserve the Tonopah Historic Mining Park, this has become one of our projects. The Silver Top mine includes not only the headframe, but the hoist house and the ore house (grizzly) too. Basically, the headframe is currently supported by four cement blocks, that were poured around the legs of it to help stabilize it years ago. The problem is that the only thing underneath the blocks of cement is some rotting wood. So the wood has rotted away and now the cement blocks are sinking down. A few years back an engineering company out of Vegas reported that it appeared to be in danger of total collapse. So, the plan is to take it apart, piece by piece, and build a cement pad or base for it to stand on, and then re-erect it, anchoring it in place. So, this is a HUGE project, and the costs are high, especially when the equipment and manpower must be brought in to work on it. But the alternative was to lose it.”

Visitor Center

Desert Queen Mine and Hoist House

The Value of Crystal Forms in Mineral Collecting

The first photo shows a closeup view of  the mineral azurite. It’s a pretty dark blue and desirable in any rock containing it. What makes it even more desirable is the mineral in  its crystal form or when arranged in a beautiful composition.

 

This second photo is of azurite and malachite from the USGS photo library of minerals. Can you see what drives mineral collectors to pursue such specimens? Although only affordable to rich collectors and museums, these examples vividly demonstrate the difference between the common and the rare. Personally, I’d enjoy any hunk of azurite I’d find.

From the USGS:

(Credit: Carlin Green, USGS. Public domain.)

Detailed Description

A sample of azurite, the blue mineral, and malachite, the green mineral. Both azurite and malachite are copper minerals that were once used as pigments but are now mostly valued as collectors minerals. They do serve as good indicators of copper deposits that can be developed. Read more information about copper here.

Sample provided by Carlin Green, USGS. Sample originated from Milpillas Mine, Mexico, and is 6.6cm in size.

https://www.usgs.gov/media/images/azurite-and-malachite

Mining Activity Clues

This terrain could be anywhere, Uniformly even but steep ground rises to abrupt cliffs. No unusual features to these regular slopes. Except this mound, in the middle of nowhere.

Visible from quite a distance, the mound up close reveals itself to be twenty-five to thirty-five feet wide with a height of eight feet or so. A trail runs across the top of it, presumably from mountain bikers using it as a jump.

At the base of the mound, and running for fifty yards or so, is a gully or a draw, obviously dug out by heavy equipment. The arrow indicates it. The spoils are the mound. Someone was digging here. It’s not the start or end of a road. It just exists. Someone was looking for something.

This area has a history of gypsum mining and perhaps that’s all the former prospectors were looking for. But any prospector today should look over the mound and draw with care. Detection is the first part of discovery.