Saturday, August 13, 2022




Hot Kalahari

Mining dark black manganese

Finding pink olmiite


A section of the Kalahari Desert, southern Africa.  Public Domain photo.

This last fall I was able to purchase, at a great price, several back issues of Rocks and Minerals, issues starting before my subscription begin.  I enjoy, immensely, reading the journal from cover to cover.  The May/April 2012 issue had, as its cover photo, a specimen of olmiite, a newly discovered mineral (2007) from the N’Chwaning Mine II, Kalahari manganese fields, Republic of South Africa.  I thought the mineral and photo were pretty spectacular and decided to look for such while touring the Tucson Shows in February.  I was always peering at the different booths and tables and was about ready to admit defeat when there it was, olmiite in a perky box on a table with many other thumbnails.  The proprietor told me he wasn’t certain what olmiite was except a manganese mineral.  He originally had two specimens but had sold one and since the show was drawing to a close I could have it for half price, $7.  I grabbed it out of his hand and handed him the cash.  At least it seemed like a good deal to me.

The photo that started it all! 

I was interested in the mineral, not only for its good looks, but also due to its rarity.  According to MinDat most olmiite specimens on the market have from the N’Chwaning Mine II, the Type Locality, but a few specimens are known from the nearby Wessels Mine (four photos in MinDat) and N’Chwaning III Mine (one photo in MinDat). Olmiite is also listed by MinDat as being found in the Långban Mine (no photos) in Sweden.  For a little interesting trivia, note that the iron ore and manganese mining at Långban has produced ~300 different minerals and is the Type Locality for ~60!

The Kalahari, home to the N’Chwaning and associated mines is the world’s most prolific producer of manganese (and also home to a famous desert). The deposits are in the Hotazel Formation of Proterozoic age (Precambrian) and are the largest land-based (deep sea deposits are larger but nearly impossible to mine) sedimentary manganese deposits in the world, perhaps covering ~425 sq. miles. The ore has been subjected to both hydrothermal alteration (temperatures up to 450°C) and to metamorphism. The origin of the giant manganese deposits has been debated for many years but remain controversial: “Proposed models cover a diverse spectrum of genetic processes, from large-scale epigenetic replacement mechanisms, to submarine volcanogenic-exhalative activity, to purely chemical sedimentation whereby the influence of volcanism is of reduced significance” (Tsikos and Moore, 2006).

Olmiite, CaMn++[SiO3(OH)](OH), is best known for its reddish pink color (pale to intense) but also occurs in various shades of raspberry, honey, pinkish tan, white to gray, while the crystals at N’Chwaning III are gemmy clear and some at Wessels are translucent clear.  However, the reddish pink is the color that sticks in the minds of collectors.

Olmiite with white crystals of bultfonteinite. Width FOV ~1.3 cm. 

Orthorhombic olmiite, a product of hydrothermal alteration, is transparent, has a vitreous luster and a white streak; hardness is ~5.0-5.5 (Mohs). Crystal habits include prismatic, spherical radial bundles, crystal sprays and what has been termed wheat-sheaf-like aggregates.  The olmiite in my collection, as do most other olmiite specimens, has a deep red fluorescence under short wave UV. 

 A closely related mineral termed poldervaarite is the manganese analogue of olmiite and they have a solid solution relationship and a long history of misidentification. Robert Cook, in the 2012 Rocks and Minerals article, articulates a great story about the history and discovery of these two minerals and presents some nice photos. Great reading.

My specimen of olmiite, as do many others, is associated with a little-known mineral (at least to me) named bultfonteinite, a fluorine bearing calc-silicate---Ca2(HSiO4)F-H2O. Calc-silicates are rocks, or their composing minerals (common minerals include diopside, wollastonite, the “garnets” grossular-andradite, and epidote) that usually form in high-temperature, contact metamorphic zones where a mafic magma (high magnesium and iron content, low silica content) intrudes into limestone or other carbonate rocks, as in a skarn. The Type Locality of bultfonteinite is at the famous diamond-bearing kimberlites in present-day Kimberley, Northern Cape, South Africa. Bultfonteinite was first found in a large, isolated block of dolerite (an igneous rock like basalt)) and shale fragments that were enclosed in a kimberlite pipe. These pipes consist of an igneous rock known as peridotite (lots of iron, silica, olivine, amphibole, magnesium) that form deep within the earth’s mantle and then rapidly and violently eject to the surface. Evidently the ejecting pipe picked up this large hunk of dolerite and shale on its way to the surface.  In the U.S. bultfonteinite is not common but is found in the famous calc-silicate rocks from the Crestmore Quarries in California.

Prismatic acicular crystals of bultfonteinite associated with olmiite shown above. Width FOV: top (spray) ~1.5 mm, middle ~1.1 cm, bottom ~1.0 mm.

Bultfonteinite is usually found as small, transparent, colorless to pale pink or white, radiating prismatic acicular crystals. Crystals are vitreous, have a white streak and a hardness of ~4.5 (Mohs).  They seem to look like many other white acicular globs of crystals I have seen since beginning my quest for nifty micromounts and thumbnails.   


Cook, R. B., 2012, Connoisseur’s Choice, Olmiite: Rocks and Minerals, Vol. 87, No. 2.

Tsikos, H. and J.M. Moore, 2006, The chemostratigraphy of a Paleoproterozoic MnF- BIF succession -the Voelwater Subgroup of the Transvaal Supergroup in Griqualand West, South Africa:  South African Journal of Geology, v. 109.

Sunday, August 7, 2022


 Often when you think you're at the end of something, you're at the beginning of something else.      Fred Rogers

On August 1, The Department of Interior published its Final Rule signaling the upcoming implementation of the Paleontological Resources and Protection Act. That is, Interior’s plans to protect and access fossils located lands administered by the Bureau of Land Management (BLM), Bureau of Reclamation (Bur Rec), U.S. Fish and Wildlife Service (F&W), and the National Park Service (NPS). In reality, these are plans to access and regulate the collection and preservation of invertebrate and plant fossils (paleontological resources) since vertebrate fossils are protected and regulated on all federal lands—if one does not have a permit just leave the vertebrate fossils alone; you may not collect them.  Essentially, these published rules regulate the collection on lands administered by the Bureau of Land Management, the 800-pound gorilla in Interior.  All fossil collecting on lands administered by the National Park Service and Fish and Wildlife is prohibited.  Reclamation is a “maybe” since the Bureau will establish special collecting areas for the public, at least that is the word from Interior.

Interior defines paleontological resources (fossils) as: any fossilized remains, traces or imprints of organisms preserved in or on the Earth’s crust. These resources are valuable because they provide unique information about the history of life on Earth. That seems a straight forward definition but there is a long history behind the collecting aspect.

Amid much controversy the Paleontological Resources Protection Act became law in 2009:  In 2015 the U.S. Forest Service (USFS), a part of the Department of Agriculture, implemented their paleontological regulations for collecting fossils, essentially invertebrate and plant fossils since petrified wood has its own regulations and vertebrate fossils are prohibited (see Federal Register May 18, 2015).  Being the old curmudgeon that I am, my Blog Post of June 21, 2015, was very critical of these new regulations and I presumably lost long time friends.  The Posting received hundreds/thousands of hits with one of the major “jokes” being short-handle shovels are OK for collecting but long-handle shovels are verboten.  In addition, I thought the requirements for permits and repositories were much too prescriptive. I have since given up on advising any child or adult about collecting fossils on USFS lands.

The Paleontology web site of the USFS ( states: Can I collect fossils?

If you plan to collect fossils, make sure you know the rules.  Forest Service regulations allow for casual collection of ‘common’ fossils that are not connected with scientific study. However, such opportunities are allowed only under certain circumstances, and collection is a privilege that carries with it responsibilities. Contact the national forest or grassland where you are interested in searching to understand what you can and cannot do, and how you might assist in reporting fossil locations to scientists. If you are unsure whether a particular invertebrate or plant fossil is common and abundant, or otherwise meets the conditions established for casual collection, a good rule of thumb is to not remove or disturb it without seeking advice from the local Forest Service office. This ensures these resources are managed for the benefit of future scientific work and for the enjoyment of visitors. Unauthorized fossil collection is a violation of federal law. You are responsible to know what and where it is legal to collect fossils. Know before you go.

On the other hand, I tried to check out requirements for collecting fossils on specific USFS “forests.”  Guess what? I simply could not locate much, or any, collecting information and certainly not information on the definition of common fossils.  That pretty much puts the stop to mom and dad taking the kids out on a Saturday field trip to hunt for invertebrate fossils---where can they locate information?  Most forests have a hot link for recreation activities where one can learn (just a little) about rockhounding, and flying a drone, but nothing about collecting fossils.  As I previously stated I no longer tell a kid where to pound on the rocks to find a fossil snail. Too complicated. In my opinion, and only my opinion, people just go out and pound on rocks and dig in the shale to find fossils.  Sort of undercover.  I am certain that USFS personnel would be happy to visit with a family about collecting (they are really nice people) but all of that takes parental time and energy, something that that most people cannot afford, or information is completely lacking.

But back to the BLM.  I believe, but my mind is aging, that BLM’s position on collecting fossils was going to be “identical” or nearly so as the USFS regs.  Such BLM information was published on December 7, 2016, in the Federal Register (great bedtime reading).  But then something, whatever something means, happened and approval of the BLM collecting regs was put on hold.  Rumors floating around here in Colorado said the “hold” was put in place by pressure from a member(s) of Congress.  And so now, five and a half years later, the “Final Rule” pops up again in the Federal Register.

I do not have the energy to completely compare the recently revised Final Rule with the 2016 version.  However, it appears that BLM listened to comments submitted by a variety of fossil collectors and rockhounds about the 2016 version.  The best that I can say is that people, especially rockhounds, were very angry with the prescriptive rules found in the USFS and BLM regulations.  All of this “rule writing” was occurring in a time of unrest in many western states citizens were complaining about presumed overreaching regulations concerning federal lands. These were the days of Bears Ear National Monument battles, etc. In reality, many rockhounds simply went on collecting  invertebrate fossils and paid little attention to rules and regulations.  As usual, most rockhounds informed professional paleontologists when they stumbled on a vertebrate fossil.

With that in mind, I believe that Scott Foss, the Division Chief in BLM (and a paleontologist I have known since his undergraduate days) has overseen a reasonable revision and workable (with a few changes) guidelines for the collecting of invertebrate fossils and plants.  The two provisions of the 2016 Final Rule that were of greatest concern to rockhounds were the permit requirements and the definition of causal collecting. 

The 2022 Final Rule states: Regulations at 43 CFR 49 (promulgated under PRPA, 16 U.S.C. 470aaa-9) require the Bureau to clarify guidance on the following topics:

1.   Paleontology Permitting. The Paleontological Resources Preservation Act of 2009 (PRPA; 16 U.S.C. 470aaa-3) and regulations at 43 CFR 49.100 authorize the Bureau to issue paleontology collection permits.  Permitting program guidance is clarified to state that the BLM will issue one type of paleontology permit and simplify the permit application process to improve public access to paleontological resources. Permit applicants are not required to possess an advanced degree in paleontology to receive a permit. Rather, the applicant must show they possesses the experience and qualifications to carry out the work that would be authorized by the permit.

3.   Casual Collection. For the purposes of casual collection on BLM-administered lands, non-vertebrate paleontological resources may be assumed to be common unless or until they are discovered not to be common (I have bolded the script).

I am still a little fuzzy about the permitting process; however,  PRPA and the regulations at Part 49 require the Bureau to do the following: 

  • Manage paleontological resources using scientific principles and expertise 
  • Maintain a program of inventory and monitoring of paleontological resources 
  • Establish an education program to increase public awareness about paleontological resources 

The regulations also require the Bureau to: 

  • Implement a program of permitting for the collection of paleontological resources 
  • Require the preservation of paleontological objects for the public in approved museum collections.

It is my opinion that most rockhounds will not need a permit since their collecting will fall under Interior’s rule for causal collecting: Provide for casual collection of common non-vertebrate fossils by the public without a permit (BLM and Reclamation lands only).

Proposed § 49.50 would clarify when a permit is required and who must have a permit. A permit would be required for collecting paleontological resources or disturbing paleontological sites except for casual collecting on certain lands managed by BLM or Reclamation where casual collecting is allowed.

Persons who need a permit are those who are studying, in detail, specific locations where fossils might be rare or scientifically important and such fossils will end up in museums.  I collected fossils, mostly vertebrates, for decades and deposited such in museums and other repositories.  I always had a permit and in the “olden days” some small federal offices and I constructed our own permits from mining or logging permits.  The best idea for persons interesting in obtaining a permit is to arrange a visit with BLM paleontologists.  The Federal Register has tens of pages devoted to “permits.”  Read at your discretion with much caffeine.

As for Causal Collecting: 3 CFR § 49.810 defines casual collection:

Casual collecting means the collecting without a permit of a reasonable amount of common invertebrate or plant paleontological resources for non-commercial personal use, either by surface collection or the use of non-powered hand tools, resulting in only negligible disturbance to the Earth’s surface or paleontological or other resources.

Non-vertebrate fossils are considered common until they are recognized to not be common. Established that Federal land managers will consult with knowledgeable paleontologists to determine which plant and invertebrate paleontological resources are not common. The BLM wants collectors to share their discoveries without fear.

And now, for more details:

CAUSAL COLLECTORS MUST KNOW THE RULES, THE NITTY GRITTY DETAILS SINCE § 49.805(c) clearly places full responsibility on persons interested in casual collecting to ascertain which bureau manages the land where those persons would like to collect paleontological resources, whether the land is open to casual collecting, and what may be collected in an area, and to obtain information about the managing bureau's casual collecting procedures.

NOT ALL BLM AND BUR REC LANDS AR OPEN TO CAUSAL COLLECTING: (§ 49.805) Casual collecting will not be allowed on BLM lands that are or become closed to casual collecting, BLM-administered national monuments, BLM-administered national conservation areas, outstanding natural areas, forest reserves, or cooperative management and protection areas, except where the bureau has specifically determined that casual collection would not impair the intent of the preservation designation. § 49.40(b) would clarify that other authorities may also be used to restrict access to or close areas in order to preserve or protect paleontological resources or provide for public safety.

ARCHAEOLOGICAL CONTEXT: (1) Fossils found in an archaeological context are an archaeological resource as defined in section 3(1) of the Archaeological Resources Protection Act of 1979 (16 U.S.C. 470bb(1)).

And now for my opinions:

RULES THAT IRRITATE #1: § 49.810(a)(2) establishes a “reasonable amount” for casual collecting as 25 pounds per day per collector, not to exceed 100 pounds per year per collector. These amounts represent a balance between PRPA's mandate to allow casual collecting and other laws that require the bureaus to protect and manage other natural and cultural resources. However, a person may collect more than a 25-pound hunk if such is needed to protect the integrity of the specimen.

My irritation with this rule is that it seems unenforceable—must collectors haul along a scale for determining weight? In addition, if a rockhound hauled home four 25-pound pieces of limestone their collecting for the year would be over.  But wait! What if the collector did not want to chance breaking their paleontological resource in the field and instead removed fossils from the 25-pound hunk while at home? After removing and cleaning they might end up with two pounds of fossil brachiopods.  What is the final total of collected paleontological resources! Would you want to take that mess to court?  It might be better to ”suggest” limits since rules are constructed to be enforced.

RULES THAT IRRITATE #2: § 49.810(a)(5) defines the kinds of tools that may be used to casually collect these resources. These tools must be small, such as a geologic hammer, trowel, or sieve; they cannot use or be operated by a motor, engine, or other mechanized power source; and they must be light and small enough to be hand-carried by one person. A tool that exceeds this definition cannot be used to casually collect these resources.

I do congratulate the BLM for ridding the regs of short handle vs long handle shovels. However, I believe the regulation is overkill and reinforces the perception that rules of the Federal Government are too prescriptive and places the federal paleontologists in a boogeyman environment.  Rockhounds know the definition of a hand tool and would want to include pry bars to crack limestone and wedges to split shale.  I also want to ask if a person with a physical handicap would need to carry personal tools?

RULES THAT IRRITATE #3: § 49.810(a)(3) clarifies that “negligible disturbance” for casual collecting means little or no change to the surface of the land, and minimal or no effect to natural and cultural resources. This proposed definition would specify that in no circumstance may the surface disturbance exceed 1 square yard (3 feet by 3 feet) per individual collector; that in cases of multiple collectors each square yard of surface disturbance must be separated by at least 10 feet; and that all areas of surface disturbance must be backfilled with the material that was removed in order to render the disturbance substantially unnoticeable to the casual observer.

Again, this rule seems overkill and unenforceable.  Instead specify that must backfill disturbance and try to leave the land surface as natural as possible—or something like that. Why should there be a difference between fossil collectors and mineral collectors in the disturbance factor?  In the USFS lands near Colorado Springs mineral collectors dig “holes”, sometimes large holes looking for quartz and amazonite. The holes are then backfilled (as least by respectable collectors).  Examine the petrified wood collecting localities in western Wyoming and notice “holes.”  But not all fossil collecting involves digging---what about pounding on limestone.  How does one measure 1 square yard?  And the rule also means that your collecting friend cannot work next to you---stay 10 feet away! Again, unenforceable, and better stated as suggestions---take care of the collecting site before you leave.

A RULE: •  Casually collected resources may be used only for noncommercial personal use, which means a use other than purchase, sale, financial gain, or research.

I understand this rule but is it enforceable?  Take a look at specimens “for sale” at rock and mineral shows and see if the specimens have provenance data.  The vertebrates contain such but invertebrates?  Not so much. The laughable rule is that “minerals” collected from BLM lands (without a permit or claim) must not be sold. Sure. Also, the BLM reg is written in a way that specifies if a collector wants to do “research” on a single specimen they must acquire a permit.  Research has a wide variety of definitions.  Of course, “research” on an important non-common specimen does not meet the meaning of causal collecting anyway.  But if a collector wants to “research” a found specimen to see if it is important, is a permit needed? There is a difference between a professional doing research for publication and a rockhound researching a specimen for identification.  What the reg should state is that collectors can’t sell of barter their fossils.

So, there it is, an old curmudgeon’s take on the new fossil collecting rules and regs of the BLM. .Much of the above information was copied directly from BLM material; some was paraphrased.  Interested readers may find the entire BLM document in the Federal register at:  43 CFR Part 49 – Paleontological Resources Preservation.   Although this is the “Final Rule” the document has a comment period that ends in 23 days. (09/01/2022).

In three words I can sum up everything I've learned about life: it goes on.         Robert Frost

Monday, August 1, 2022




Many times, during my career as a rockhound, I have been visiting a rock and mineral show/shop and have noticed a lonely looking mineral that “lookers” seem to push to the side.  In my mind these specimens deserved a more solid observation.  Usually the specimens were broken, grossly misidentified, glued in ugly cardboard boxes, etc.  However, if you love minerals, minerals will love you back---and there it is, a mineral in a nice perky box that needed a home.

But actually, a mineral hunter like me also needs a sense of humor and “lots of luck.”  Sometimes it works and you get a real jewel. Sometimes you need to make it a jewel, like the mineral tungusite.  When I noticed it at the show the first think that struck me was, “nice new perky box. That is worth a buck, and what in the world is tungusite?”  My curiosity was getting the best of me, so I took it home and promptly forgot about it until this week—and then I thought “what in the world is tungusite?” Turns out it is a hydrous silicate of calcium and iron [Ca4Fe2Si6O15(OH)6] first described from the Lower Tunguska River, Eastern Siberia Region, Russia, and not found in many other places (Canada, Iceland, India, Portugal, Siberia, Ukraine, and a couple of localities in the Los Angeles area). It does not seem common at any locality, even the Type in Siberia. In all places tungusite forms as a crust in vugs and cavities during the late stages and lower temperatures of hydrothermally altered basalts.  At the TL many of the associated minerals are zeolites but tungusite’s special close friend is gyrolite, a mineral once considered a zeolite.

Platy aggregates of tungusite showing the radial-fibrous structure. Width FOV top ~1.8 cm.

Stacks of laminae clearly seen.  Width FOV ~1.1 cm.

At first glance tungusite appears to have a metallic sheen.  With closer examination one observes the mineral is composed of thin, flexible, radially fibrous plates or laminae that are translucent or transparent. These plates are quite soft at ~ 2.0 (Mohs) and were originally described as yellow green to grass-green in color.  However, as the amount of iron in tungusite varies considerably from almost nothing (white tungusite) to a very dark green, depending on the amount of iron—the more iron the darker the color. A lighter green is only seen when thin sheets are separated from the mass along good cleavage planes. In addition, in close observation, the luster is more pearly than metallic.

As I noted, tungusite often occurs with gyrolite, a sodium calcium hydrate [NaCa16Si23AlO60(OH)8-14H2O] that is often mistaken for a zeolite as it is associated with zeolites in vesicles, fractures, and vugs of hydrothermally altered basalts, or in skarn-like deposits. It is found in basalts around the world as light colored, often white or brown or green, platy or lamellar masses of crystals that have a vitreous or subvitreous luster.  These masses are soft at ~2.5 (Mohs) and brittle. The mineral is the namesake of the Gyrolite Group where cations vary: if iron is added (tungusite), strontium (cairncrossite), or manganese (orlymanite),

Gyrolite collected from the basalts at Lonovala Quarry, Pune District, Pune Divison, Maharashtra, India. Poona, India.  Width of specimen ~4.5 cm.

Photomicrograph of a section from specimen above showing thin laminae producing a lamellar structure.  Width FOV ~1.0 cm. 

Digging a little deeper, actually much deeper, into a very complicated (at least with my knowledge) paper by Ferraris and others (1995), researchers found that the chemical variability in tungusite is due to microscopic intergrowths of gyrolite between lamellae and also defined a substitutional solid solution between the two minerals.  They also noted that “white tungusite” may be iron-bearing gyrolite, or iron-poor tungusite.  Wow, I thought the recent paleontological arguments about the number of species in Tyrannosaurus rex (Carr and others, 2022)) was complicated but iron poor tungusite vs. iron-bearing gyrolite “takes the cake”! 

Thanks to Ragul Ebinezarm.



Carr, T.D., Napoli, J.G., Brusatte, S.L. et al. Insufficient Evidence for Multiple Species of Tyrannosaurus in the Latest Cretaceous of North America: A Comment on “The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus”. Evol Biol (2022).

Ferraris, G., Pavese, A., Soboleva, S.V., 1995, Tungusite: new data, relationship with gyrolite and structural model: Mineralogical Magazine, no. 59.