Heulandite Discovery

Heulandite Mining in 2003

Rat's Nest claim, Challlis, Idaho


It was Monday morning, May 26, as I drove through the ranch and up to the Rat's Nest claim, I was the late comer, the trackhoe owner/operator, John Cornish (claim lessee and specimen miner) and his friend and partner Fred Gribler were already there, hard at work; I could see the excavator working it's magic on the claim in the distance as I drove over the grass and sage brush covered hills. It was a little after 8:00 Pacific time which I was staying with, while down here in Challis it was Mountain time, so the work had been going on for over an hour when I arrived.

After driving to the end of the road ("jeep trail" actually), I switched foot gear to my work boots, put on my hat and sun screen, grabbed my pack, hoepick, video camera, digital camera and water, and hiked the three hundred feet up to the pit. On arrival I was greeted all around from across the pit. I set up the video camera and began shooting video of the operations. I was pleased to see a good quantity of heulandite specimens already sitting on the previously cleared bench which marked the top of the heulandite-bearing andesite flow. This bench was cleared with this same excavator for me and John last year. Now, with the andesite exposed, it was time to chew away at this layer and free some world class heulandite and mordenite specimens.

The best of the first day, a cabinet specimen with large heulandite crystals and some excellent mordenite.

John Cornish in pit watching for heulandite geodes as the trackhoe is used to move the enclosing andesite.

Fred Gribler showing two of the specimens passed up from the pit by John.

The day was looking good. Sunday had proven to be a rather tenuous collecting day. I drove down from home that day, and spent the afternoon looking for fluorite in the mines near Challis. Unfortunately, it was a hot, mostly cloudy day, and much of the time was spent trudging back to the truck for protection from thunderstorms. (Fluorite collecting wasn't very good either, I kept one "iffy" specimen with a pack rat trail worn into it... .) That day John and Fred were setting up their camp at the edge of the ranch through which we pass to get to the claim, and later on Monday, John told me about how severe the storms were there--lots of rain, and the wind so strong at times that his tent was flattened and a couple poles broken. Fortunately he managed to fix it up, it was standing when I drove past.

The weather continued to be fairly good all day. The clouds stayed, and the temperature probably didn't get any higher than about 80 degrees out here on the claim. A fairly nice day, with no thunderstorms, compared to the way it often is on this hill.

The excavator getting ready to remove more of the rock, note the large calcite-mordenite geode exposed in the wall.

John lifting a large heulandite specimen from the pit.

As collecting went, the day was good. John kept the excavator going most of the time for about three hours. This produced enough specimens this first day that he was unable to get them all trimmed and boxed by dark. John had come down to mine specimens, I came down to do a little collecting, take pictures and videos and lend a hand some. Fred was doing some of the initial trimming (freeing geodes and sections from the large rock they often broke out of the ground in), and hustling specimens from the edge of the pit to a safe distance from the operation. It was no problem keeping us all busy. After shooting video and taking pictures for a while, which I did each of the three days, I joined John in the pit watching for heulandite as the excavator chewed into the andesite.

Several heulandite and mordenite-bearing geodes exposed in the wall of the pit, waiting for more rock removal so they can be collected.

John passing a fine heulandite and mordenite specimen out of the pit to Fred.

After the excavator was stopped, I spent a few hours handworking in the pit where a few heulandite-bearing geodes were exposed. Fred spent some time hand working another area. Later in the afternoon, they began trimming, wrapping and packing specimens. I did a little of that, but mostly kept busy on other things. At 6:30, I decided I had enough, had to have dinner, had photos to download, field notes to write and other daily chores to tend to. Looking at John and Fred's work load, I wrongly surmised they would be done in a couple hours. I camped below the hill for the night, figured by time we all were done with our work, there wouldn't be time for socializing, so there was no reason to drive down to their camp at the ranch (guessed that one right!). As I enjoyed my time finishing up my day and it started getting dark outside, I noticed they hadn't come down yet. A few minutes after 9:00 (10:00 Mountain), I saw them making a trek to the truck with boxes of specimens. I was comfortably sitting in the cab of my truck writing on my computer. Felt a lot better than sitting on a rock in the pit! An hour later, it was looking kind of dim outside and I expected them to be down, but as I looked up at the pit, I could see their silhouettes walking the hill back to the pit from another trek to the truck with boxes of specimens. Finally, at 10:20 (of course that was 11:20 Mountain time that they were now working under) they finally came driving off the hill. At that time I was glad this wasn't my mining operation!

Part of the "catch" of the first day of mining.

John with the best specimen collected on Monday, May 26; a close view of this specimen is at the top of the page

The next day went much the same. John and Fred were hustling specimens out of the pit as I shot video and took a few pictures in the morning; then I joined John in spotting heulandite as the excavator chewed away at the andesite. When the excavator was stopped at noon, there was more than enough specimens to keep us all busy trimming and packing for the rest of the day. We didn't leave the pit with any geodes showing, so with nothing better to do, I volunteered my time to be John's slave and help him and Fred so that maybe they could get off the hill before dark. For the next nearly seven hours, I trimmed specimens, as did John, and we managed to keep ahead of Fred who wrapped and packed specimens, and brought specimens to us to trim. After a while, I decided that I needed to move a little, so began getting up to retrieve my own batch for the next trimming session. That worked well, sit for a while trimming, then get up and walk a little to get more to trim.

Before we started trimming, Fred applied his expertise at stringing up a tarp to provide some shade. That was a welcome addition to the operation. The day was cloudless, and with the bench/pit facing east-southeast, it was hot up there. I never checked the temperature at any time on Tuesday, but comparing it to Monday and then Wednesday, my guess is it was around 80 in the hottest part of the afternoon. The shade of the tarp made the work reasonably comfortable. I worked until after 6:30 on trimming, then John who had spent the last half hour or more breaking the geodes out of large rocks, decided we had better move the untrimmed specimens further away from the edge of the pit, or on Wednesday they would be in the way of the excavation. We did that until a little after 7:00, and I called it a day and went down to my camp, dinner and writing. John and Fred got off the hill a little after 8:00, but hadn't completed trimming and packing specimens.

Another very fine specimen with wonderful pink heulandite on a matrix of fine mordenite.

A large, over 14 inches, geode showing two compartments separated by platy calcite, waiting to be trimmed into specimens.

Wednesday started about the same, but it already felt hot when we started work. John decided to have the excavator work until mid afternoon, then not work on Thursday. Hopefully, he and Fred would get caught up trimming and packing specimens by Thursday night. Due to the hustle of the work, and the fact that the excavation of the pit was eating into what had previously been the staging area for storing and trimming specimens, the tarp was down for most of the day. That didn't matter much, none of us were sitting around anyway.

The area being worked this morning was not as productive as the average up until then. After watching the excavator chewing away at the rock and very little showing I was surprised to see how much material had actually been produced when I looked at where they were sitting on the floor of the bench. Even this area of low production had produced a lot of material, John and Fred were going to be working hard that afternoon and Thursday to get ahead of it all. The last area worked was the outside edge of the cut. It started producing a fairly good amount of material, with an uncommon amount of calcite. Most of the calcite was not specimen material (most calcite crystals are frosted/etched), but occasionally, there was one of better quality. Included in this was the wonderful specimen illustrated below with light yellow tabular pseudohexagonal crystals with heulandite and mordenite. This is the only truly good calcite specimen from the mine. There are others that are good locality specimens, and a few small crystals that are lustrous, but no other specimen is one I would call a good calcite specimen. It made John's day, and will go into his personal collection.

Platy calcite in a cavity with heulandite and mordenite. Platy calcite is common, but only occasionally does it show fairly good crystals, most plates are irregular and show no terminations. This one was not recoverable as a specimen, it broke up during trimming. That wasn't a problem considering it really wasn't as good looking as this photo might suggest. The field of view is about 10 inches, a bit large for a mediocre calcite specimen anyway.

The best calcite specimen recovered from the Rat's Nest claim in four years. It shows an unusual tabular pseudohexagonal form, with heulandite and mordenite. Calcite crystals are nearly 2 inches across.

When the excavator was shut down for the day, I called it quits for this trip. It was hot up there, and the wind had come up. That didn't bode well, it often blows hard and steady up there, for days at a time. A little later, when I got in the truck and drove off, the thermometer read 89 degrees, and when I drove through Challis, it was 93.

I wrapped up the few calcite specimens I'd kept, a couple nice small ones with crystals under 1/2 inch, and some that only a locality collector would love (and this is my locality...). This wasn't really a specimen collecting trip as it turned out;, but I would pay for one hour of excvator time. I had one very nice cabinet specimen of mordenite with heulandite, another good mordenite specimen, a cabinet heulandite specimen of good average quality and one large heulandite geode, nearly complete of questionable quality, depending on how well it "opened up" inside*. It was a grand adventure though, working in a specimen mining operation on my discovery, enjoying three busy, hardworking days. * Note from the winter of 2003-2004: the nearly complete geode turned out to be less than average quality. It didn't open up completely and only had small heulandites and fair mordenite. After over an hour of carefully trimming the matrix, it broke in half showing the disappointing interior. It was worth the attempt to maintain it as a whole geode; maybe the next one that comes out complete will be a killer specimen!

John proving that there are better things to do sometimes than work in the hot sun in a dry, dusty, rocky pit. Looks like he found the only shade on the hill!

A nice specimen of laumontite, an uncommon mineral at the mine. Like all laumontite it rapidly became a pile of white dust, but it makes a very fine mineral photograph when fresh.

John and Fred will probably be done working the claim on Sunday, and then have a long drive home.

Anyone looking for good Idaho heulandite or mordenite (or combination) specimens can email John at: j&gcornish@tenforward.com. Specimens are available in all sizes from small miniature (maybe even a few TNs) to large cabinet. Most of the heulandite is pink, and much of it is world class with plates covered with crystals up to an inch long, or crystals over an inch scattered over the specimen. Many of the large geode sections or geode halves are spectacular. If you appreciate the scarcity of good mordenite specimens, you know these are the best in the world.


Copyright 2003,2004 Lanny R Ream