“Provenance refers to the origin, source, or the chronology of the ownership and custody of an item.” It essentially answers the questions of where something came from and whose hands it passed through over time. (Merriam-Webster.com).

Well curated mineral collections have always been seen as a valuable sources of information for other collectors doing similar research on specimens in their own collections. Historically, that usually meant saving all labels, notes, and descriptions that may have accompanied a specimen. These written artifacts provide clues that could lead to interesting stories of the person, location, or period lost over time.

Following is an example of how just one small clue (on a label or note) can lead to details considered important by mineral collectors in the provenance of a specimen.

Pyrite with Sphalerite, Belmont Mine, Butte, Montana. 4.8cm x 2.5cm x 2.5cm

Ex. Bill Williams Collection, Gene Meieran Collection, Ed McDole Collection.

The specimen shown here has labels connecting it to three well-recognized mineral collectors, Bill Williams, Gene Meieran, and Ed McDole. Most notably, the provenance information on the Meieran label states that the specimen came from the legendary Ed McDole, a well known mineral collector/dealer active in the 1940’s through 1960’s.

The following excerpt is from Mineralogical Record Biographical and Label Archive for Ed McDole: “In the late 1940s and 1950s Ed worked two shifts as a contract miner (paid by the ton, so he wasn't rushed) in Butte, one shift under his own name and another shift, probably at a different mine, under an assumed name. He apparently did this mainly for the purpose of collecting minerals. In his later years he worked out of Ely, Nevada, and lastly lived in the historic Grand Imperial Hotel in Silverton, Colorado. In addition to his own collecting activities he bought minerals by the powder-box-full from other miners coming out of the various producing mines, especially the Leonard mine. The quality of McDole's Butte specimens is legendary, and he was certainly responsible for saving many of the finest specimens ever to come from that famous locality” (https://mineralogicalrecord.com/biographies_labels/mcdoleed/).

There are very few of Ed McDole’s documented labels or notes in existence today (he was a very private person), so almost all of the specimens attributed to him were noted by other well-respected collectors on their provenance labels. If the Meieran label had not been saved, this otherwise average looking Butte mineral specimen might not have the collector attention it gets today.

Dan Evanich

A couple of weeks ago I posted an image of a Butte enargite and pyrite mineral specimen (see the image above) that needed a moderate cleaning and edge trimming to restore much of the original look. The work has been completed now and you can see it at this link to the Facebook page “Richest Hill on Earth”:

https://www.facebook.com/groups/2050996864913862/permalink/27457541887166010/

I’m a bit partial to this “holy grail” Arizona mineral locality since I was fortunate enough to have identified one of the 11 type locality minerals that came from the Mammoth-St. Anthony Mine. In 2022 I noticed that one of my Tiger mineral specimens had an unusual looking group of small crystals. It proved to be a unique new mineral species and with the help of Dr. Hexiong Yang at the University of Arizona, it was approved by the IMA and named evanichite in July of that year. To date, only two specimens have been confirmed, both from Tiger. But that’s not the main reason I’m writing this article. Since then, I have examined many more old collection Tiger specimens, and late in 2025, I found another specimen with some unusual looking yellow color micro crystals. I sent a sample to Dr. Yang and he had EDS and XRD analyses done at the University of Arizona lab with interesting new results. The small micro size crystals had the chemistry of a known species named fornacite, but there were some important differences which showed up and provided the subject of this article, “a new polymorph mineral.”

Fornacite Polymorph from Mammoth-St. Anthony Mine, Tiger, Arizona.

Yellow fornacite polymorph crystals on colorless quartz. Photo by Ron Gibbs 2025.

The photo above, taken by Ron Gibbs, shows yellow color fornacite polymorph crystals with green malachite and colorless quartz crystals. Analyses conducted by Dr. Yang show that the mineral is a new variation in crystal structure of the confirmed species fornacite. In previous years, this variation would have been sufficient to identify the mineral as a separate species and given a new name. But starting in 1998, the International Mineralogical Association (IMA) determined that “most polytypes and polytypoids (specific types of polymorphs) are not to be regarded as separate mineral species.” (https://mineralogy-ima.org/about.htm).

So what exactly classifies a mineral as a polymorph of a species rather than a new mineral? Mindat.org provides a clear definition: “A polymorph mineral is a mineral that shares the exact same chemical composition as another mineral but possesses a different internal crystal structure. This phenomenon, known as polymorphism, occurs when minerals crystallize under varying temperature and pressure conditions, resulting in distinct physical properties.” (https://www.mindat.org/) For reference, the IMA approved formula for fornacite is: CuPb₂(CrO₄)(AsO₄)(OH).

Green malachite and colorless quartz with yellow fornacite polymorph micro size 1-1.5mm crystals. Overall specimen size 7.5cm.

XRD Analysis Results

XRD analysis results for the new fornacite polymorph showing the unit-cell parameters from the single crystal X-ray diffraction:

The unit-cell parameters:

Fornacite: a = 8.1010 Å, b = 5.8930 Å, c = 17.5470 Å*, β = 110.00°

New Polymorph: a = 8.0829 Å, b = 5.9224 Å, c = 8.7832* Å, β = 90.000°

*Note that the c-dimension of the new polymorph is only half that of fornacite which shows a good indication of two different internal crystal structures.

EDS Analysis Results

The ideal atomic ratios for the major elements are Pb:Cu:Cr:As = 2:1:1:1, but for this analysis, Pb:Cu ~1:1. Some Cu may be substituting for Pb. It was unusual to find that the Cu content was considerably higher.

Mineral analysis methods are advancing rapidly today with the advent of artifical intelligence contributing to quicker and more precise conclusions. As we have seen and will continue to see, the guidelines and definitions of the necessary characteristics that determine whether a sample is a new mineral species or not will continue to be refined to even more exact criteria. Many of the prior analyses that were done confirming new mineral species in the past are being scrutinized closely today with more advanced technology tools. Don’t be surprised if the number of discredited species begins to rise and the identification of more polymorph variations rather than new minerals are confirmed.

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When manganese is combined with other elements like carbon, silica, or iron, (as it did in the Butte mining district), a wider range of color occurs in the minerals produced. In the following paragraphs we’ll take a look at the reasons manganese became so important to the economy of Butte and the variety of minerals that came from the ore mined.

Historically Speaking

Manganese mining in Butte, Montana, became significant during World War I (1916–1918) due to high demand for steel production. Silver and copper were the most important economic metals from Butte being produced at the time, now manganese was at the dawn of a new equally important era for the mining district. While initially considered waste rock, manganese production ramped up in the 1920s through the 1940s, with peak production occurring during World War II.

How much manganese was being mined during this period? During the early 20th century, specifically around 1917–1918, Butte, Montana, was a notable producer of manganese, with estimates suggesting reserves of several hundred thousand tons of manganiferous material, including over 400,000 tons of siliceous manganese ore estimated around 1917–1918, in addition to high-grade carbonate ores. (Reed and Dilles: MBMG Special Publication 122: Geology of Montana, vol. 2: Special Topics).

Mineralogically Speaking

Numerous manganese mineral species occur in the ores of Butte. Following is a list from Mindat.org of the common valid species with images of specimen examples from my Butte collection along with a few descriptive details and comments.

1. Alabandite (MnS): A basic manganese sulfide most often in massive form from Butte, but rarely in crystal form.

2. Manganite (Mn³⁺O(OH): A widely scattered manganese oxide mineral in the Butte peripheral zone especially in the mines West of Butte proper (ex., Burlington mine, Mapelton mine, Travona mine etc.). Occasionall found in distinct bladed crystals within vuggy quartz seams

3. Pyrolusite (Mn⁴⁺O₂): An important manganese ore oxide with occaional fibrous crystal structure showing. Mainly a massive gray color ore from Butte

The focus now moves to two of the more recognized manganese minerals that also produced thousands of tons of ore (and more colorful mineral specimens) during the period ; Rhodochrosite and Rhodonite.

4. Rhodochrosite (MnCO₃); The carbonate mineral variety of manganese found across a wide area of the Butte mining district, most prominently in the Peripheral Zone.

Several variations in crystal forms of the rhodochrosite from Butte are known beyond typical rhombohedral. Among these the following occur:

Rhombohedral Crystals: The most common form, often found as large crystals or complex clusters on a matrix of quartz or manganese minerals

Rounded/Curved Rhombs: Crystals can display rounded or composite faces sometimes forming a mound of crystals or “knobs”

Massive & Granular form: Frequently occurs in granular or compact forms within veins.

Stalactite form: Narrow pyramidal “finger-like” formations.

Deep translucent pink-red color: Specimens with deep color from Butte are known from several mines, but they are not common. Speculation is that most of these richly colored examples came a from few noted mines like the Lexington and the Travona (and they did), but it’s based mainly on the early examples with reputable, well-documented provenance.

5. Rhodonite Group (CaMn₃Mn[Si₅O₁₅]; Manganese with silica. Some preliminary analyses indicate much material currently called rhodonite is actually vittinkiite, ferrorhodonite or pyroxmangite, and probably should be termed rhodonite group until analyzed. (Mindat.org 2026).

   

But wait, Butte’s manganese mineral species get even more complicated! From Mindat.org we find a description of the complex suite of Manganese oxide minerals that are difficult, if not impossible, to identify as a singular species for any given mineral specimen. Many of these varieties undoubtedly exist in Butte’s manganese ores:

“Manganese Oxide; A generic name usually applied to any unidentified, manganese oxides and hydroxides, especially where they are fine grained, and often intermixed, including: Akhtenskite, Asbolane, Aurorite, Birnessite, Buserite, Coronadite, Chalcophanite, Cryptomelane, Feitknechtite, Groutite, Hausmannite, Hollandite, Manganite, Psilomelane, Pyrochroite, Pyrolusite, Ramsdellite, Ranciéite, Romanèchite, Todorokite, Vernadite, Wad.”

In conclusion, the importance of manganese production in Butte is obvious. In the early 20th century mining period of Butte the local population grew even larger by drawing thousands of people from all parts of the world in search of steady work with a chance for a better life. At its peak, the surrounding population of Butte grew to an estimated 95,000-100,000 people in 1918.

Dan Evanich

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Enargite and Pyrite, Butte, Silver Bow County, Montana. 12cm x 9cm x 5cm

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Welcome to the introductory post for my Substack page discussing all things related to the minerals and mining history of Historic Butte, Montana, also known as “The Richest Hill on Earth.”

The Butte Mining District has well over one hundred different types of mineral species that have been confirmed and much of the writing I do will be to share descriptions and photos of them. Hidden beauty will be shown in many of the images of the crystallized specimens as well as the more common ore samples. I’ll be sharing my observations of the species characteristics that help with accurate mineral identification of the specimens which I have acquired over the last 20+ years of collecting Butte minerals.

Look for a new post at least once a week, but don’t hold me to that, since I am away for periods of time on multi-day mineral collecting field trips in Western US mining localities.

Back to the introductory title before closing, here’s a look at an honest to goodness, really good 3” wide covellite specimen from Butte, Montana, The Richest Hill on Earth.

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