Bright Colors

By Bill Shelton

Proustite, Pyrargyrite, Pyromorphite, Mimetite & Vanadinite

I can write pages on all five species - for a collector, they all matter since availability is fair or better and all will brighten most any display.  According to mindat.org, here are the locality numbers for this group.  Proustite – 698   Pyrargyrite – 1,300   Pyromorphite – 1,510   Mimetite – 993   Vanadinite – 605.   The first two are the least common and, unfortunately, rather expensive members of this group.  For classic localities, one should consider the examples given below.  Proustite and pyrargyrite are especially noted from Andreasbrg, Freiburg and Pribram.  Also, Bolivia, Chile and Mexico.  U.S. localities include Colorado, Idaho, Nevada and New Mexico.  Cobalt, Ontario is also important.  Pyromorphite, with the most given localities in the group, is noted from Ems, Pribram, Beresovsk, Cumberland and Leadhills.  U.S. localities include Phoenixville, PA and Idaho.  Mimetite can be found from Tsumeb; Australia is another possible choice.  Mexico is famous as well.  Vanadinite can be found from Morocco and Africa amongst other worldwide localities.  U.S. localities are very common in New Mexico and Arizona.  I have found Morocco to be a very prolific source and one could buy as many as one wanted with ease. It may have the fewest localities but it seems to be the most available. 

 Color is a major concern and I suggest buying the brightest, pure shade you can find.  For example, vanadinite from Morocco is often an unpleasant hue with orange and/or brown mixed with red.  Get yourself an excellent pure red specimen.  They occur on black matrix and, as such, can be very dramatic.  The case lighting will affect the appearance so pay attention when selecting case lights for your samples.  As some of you know, red is a scantily represented color in the mineral kingdom.  The very best proustite can be a vivid red but exposure to light may darken them so keep that in mind.  Small crystals with excellent color have been recently available from Morocco but large, excellent crystals are very rare.  Chile produced some of the best pieces; these will likely cost a lot!

 I do not cover micromounts much in my articles but here we can find affordable representatives of most all the 100 species in this series.  You can find modest pyromorphite examples in Massachusetts and Pennsylvania with a little luck even today.  In the past, Connecticut produced examples at Canton and Thomaston (pyromorphite) but mostly micro size crystals.  A cursory glance suggests some, and perhaps all of these five species can be found in any size range.  The last three are likely to be more moderately priced. 

 A couple years back, I helped prepare and sell about 30 large boxes of mimetite.  They were white to clear, mostly small crystals; all were on dark matrix from Mexico.  Hundreds of samples were sold; the market seems to have absorbed them all; this is actually a typical circumstance.  Samples were highly lustrous and glittered when placed under any type of light.  You may already have one in your collection. 

 Some minerals seem to be stellar examples of misdirection, etc. and, as such, present a collector with perplexing problems; noteworthy might be turquoise.  Rarely have I encountered obvious defraudulent specimens within this group under consideration here.  I have seen pink fluorite and spessartine samples where additional small crystals were glued onto the matrix to provide a “better:” specimen.  None of this has, so far, been seen with these species.  In the event a specimen looks too amazing to believe, examine it with care for obvious glued connections.  A black light may be useful in this respect.  Much has been said regarding fakes and frauds before – you can check on the internet for a detailed report on this topic.

 Incidentally, all of the five species are good indicators of possibly valuable ore deposits.  Proustite and pyrargyrite are often associated with silver deposits worldwide.  Pyromorphite is found with lead and even zinc deposits but it only contains lead.  Mimetite, which is noted for lead, also contains arsenic.  Finally, as the very name suggests, vanadinite will contain vanadium; it also has lead in its formula.  Generally, we would consider vanadinite as a source of vanadium and a minor lead ore.

Azurite and Malachite

By Bill Shelton

Recently, we held a class on the two species listed above – apparently a few people thought it was a good lesson and would like a short review of the highlights on the website for TGMS. 

 I think the associated species are worth knowing about and please note six are found with both azurite and malachite.  They are cuprite, tenorite, calcite, chrysocolla, copper and wad – all according to Dana texts we consulted.  Azurite also may be seen with Fe oxides and chalcedony.  Malachite may come with chalcocite or limonite.  Of course, there are others but these are perhaps the most common and well-documented associates.  We also find pseudomorphs are commonly noted and for azurite we include azurite after cuprite, cerussite, tetrahedrite and gypsum. In the case of malachite, it is noted to replace azurite and cuprite.  There are others as well but they are probably less common or widely known than the examples given. 

Chemistry is one good way to compare minerals and here we find a great deal of similarity – they are both basic cupric carbonates.  For your own benefit, take a look at the formulas on mindat.org or in your favorite textbook.  While azurite has 69.2% CuO, malachite has 71.9%CuO – a minor difference.  Malachite has, upon chemical testing, shown to contain occasional traces of zinc.  Azurite is in contrast, ordinarily quite pure. 

Because of this, you may expect the properties to be even more similar than they are – the actual results may be a bit surprising.

 Clarity is dissimilar in that azurite is transparent to translucent while malachite is translucent to opaque.  This will best describe the majority of samples one may encounter – exceptional examples may be good additions to your collection.  Crystals of malachite are rare and almost always twins.  Azurite, on the other hand tends to be common as crystals and here twins are rare.  Color is quite different and azurite is azure blue to very dark blue. Most malachite is a bright green and may also be deeper shades that approach black which will sometimes be seen in banded pieces and also on crystals when they are found.  Micro size crystals are noted to be green and transparent but such material is not usually seen.  Malachite is also likely to be massive and can be botryoidal in form.  Azurite is often in crystals but botryoidal and stalactitic forms occur as well. 

Using mindat.org, I found that malachite has 5,478 photos and 11,798 localities.  Azurite has 6,274 photos and 5,340 localities.  An area of controversy concerns the type locality for azurite – some claim it to be Chessy, France but I am inclined to say there is no type locality because, as it says for malachite, it was known since antiquity.  You should look at the lists for the localities given on mindat.org – there is a lot of valuable data here. 

According to Minerals and their localities (2015) malachite is “a very common oxidation product of chalcopyrite and other secondary Cu sulfides occurring with azurite and some other secondary Cu minerals in gossan.  It is widespread throughout the world”.  Azurite is a “very abundant product of oxidation of Cu sulfides and it nearly always accompanies malachite.  The Handbook of mineralogy lists aggregates to 9 cm and exhibiting several forms (maybe 20 or so) for malachite.  They list crystals to 30 cm for azurite with typically complex crystals and over 100 forms.  You should look at the Mineralogy of Arizona for the long lists that they contain – you will find a lot of places for both species on a county by county basis. 

We do not make a huge effort to cover gem data but it seemed appropriate to do so and chose several sources. First, the Color encyclopedia of gemstones, where we find azurite as a source of rare faceted stones, mostly less than a carat but cabochons may be up to several inches.  Malachite is virtually unknown as a faceted stone but cabochons and carvings are very frequently observed.  If faceted, the stone would be under ½ carat and opaque. As you know, we do not usually bother to facet a stone when it is not quite transparent.  Masses to 50 tons are also noted, so we should take that fact into consideration.  Fluorescence, in multiple sources is said to be non-existent. 

 As a final note, we can find information as to what causes the two species to be different colors.  It seems that the structure is different enough to affect the absorption of the copper ions and perhaps the bond size as well so that azurite produces a blue color unlike the green we see in malachite.  In 1979, Marfunin said the structure in azurite was arranged so that the copper ion was in elongated octahedral coordination while malachite was in octahedral coordination – the difference may translate to bond length and that can cause a slight change in the absorption and color you actually see.

Collection Building

By Bill Shelton

Collections might seem to have a life of their own, but that is not the case for many of us. We have a plan of sorts that helps guide us when it comes to acquiring and managing samples in our cabinets.  Exactly how can an individual proceed?  What are some of the many decisions they may make to expand and mature their own collection?

This can be a very complex process; we may not be doing the same things as other collectors.  Living here in Arizona, it is likely that you at least think about a suite of minerals from here – but do you also choose certain places; i.e. Bisbee and Ajo or places in a particular county like Pima?  Maybe the selection process will involve a chemical context such as lead bearing species or perhaps secondary minerals (that will involve a chemical signature) and again you can limit the choices to certain areas.  One can easily do a collection of unusual crystal forms or more or less common species from little-known localities. 

Did you ever go to mindat.org and just enter Bisbee or Ajo and see what pops up?  Well, when I did there was a very brief list for “Bisbee” and prominently displayed we find 326 species and varieties and almost no other places were included.  Ajo on the other hand will show pages of worldwide places that contain “ajo” anywhere in the name and among them is Ajo, Arizona with 127 species and varieties listed.  In terms of worldwide localities, Bisbee ranks very high based on the number of noted species and varieties.  As a collector, you may decide to try and get all the macro size species or only the rarer species found in selected localities. It is all about choices and what you determine you would like to do. As one can see, a collector might choose to build a collection of all the species that are found in both of these districts.  There will be quite a few since the deposits are somewhat alike and azurite is famous from both as an example. 

We found 286 valid species for Bisbee and 100 for Ajo – also there are 6 type minerals for Bisbee and 2 type minerals for Ajo.  One can see where this may lead – type collecting has always been a part of our hobby. Besides, you only need to get 8 specimens.  You may already see that it is a trap of sorts since that will be easier said than done.  Add a few type species from other places and you are on your way to a new collection or perhaps a new sub collection.  How many places have odd or unusual quartz crystals here?  That can be a topic to investigate and perhaps you will add it to the growing collection you are creating.  I bet you will have a lot more than eight samples if you choose to do this!

As for me, I seem to have this penchant for former Soviet Union minerals and that is a lot of area and species to cover, but it does focus me away from collecting everything.  Among the many items, I have a small suite of odd eudialyte group minerals and seem to think it is a good idea to get more of them if they ever come available.  I also feel a need to get as many different Dalnegorsk minerals as possible in macro specimens and with hopefully decent crystals present – as you see, I must be picking and choosing, but then you get to omit things you really don’t care to have anyway.  But the disease is never cured since I must have twenty or more beryls form the Urals and so on and so forth.  So, why so many beryls you may ask?  Well, I like them, and why not if they please me?  After all, you make up the rules for what will be in your collection and then follow or change them to suit yourself.  

The number of pieces you may have can be an issue.  It has been said that some collectors add one and get rid of one so they keep the same number of species in the collection.  Well, I seem to add but not get rid of much and think a lot of you do the same thing.  After all, the best collections are in museums and heaven knows how many they may have. Well, actually I do know – the American Museum of Natural History has about 100,000 minerals according to their website – it seems to me like a lot more may be there. They also claim 3,700 gems and actually have 5,000 minerals on display.  So, we now know that it is imperative to go to New York and see all 5,000 of them for ourselves.   According to data from the internet, the Smithsonian in Washington, D.C. has 413,616 records (for specimens) and has 560 type mineral specimens.  The Sorbonne in France has 13,000 samples with 1500 on display.  The University of Manchester (Manchester Museum) states that they have some 17,000 specimens of meteorites, gemstones, ore samples and rare minerals. I also found the British Museum claims to have 80 million specimens including minerals and much more.

Did you realize that a great many pieces came from private collectors in the past? Even today, we see collectors sometimes choose to donate their pieces to museums. So there is another thing you can think about doing at some point.  If you ask a museum, they might tell you what they want and then you can work together to achieve a goal. They will probably like to have all the type material and a full set from Bisbee will no doubt be of interest too.  As a cautionary note, museums do reject donations when the specimens are not sufficiently good to achieve their purposes.  You should plan ahead if you have a notion of donating away your collection at some time in the future.  With a good plan, you help build their collection just as you have built your own.  

Collecting Eudialyte

By Bill Shelton

Eudialyte is a proper mineral species and the name of a mineral group.  There are 26 species within the group; I find about 20 are very restricted in their occurrence meaning they are present at only one or two localities.  The chemistry and structure of most of the species have only been studied in detail in the last 10 to 15 years.  Variability in the chemistry was noted over 100 years ago and this is one reason why we now have so many species.  In some ways, this is reminiscent of the similar circumstances surrounding the tourmaline group.  Fortunately, the name of that group (tourmaline) is not currently accepted as a mineral species.  As a collector, I am interested in similarities and differences between species within a mineral group.  The locality data is also significant to me; for the eudialyte group many species occur within the former Soviet Union which is my main collecting focus.

Based on webmineral and mindat, I have found the dates for all 26 species in the eudialyte group.  They are, indeed, a new group because all of the species were identified since 1990 with one exception.  Eduialyte dates to 1801 and has been accepted for a very long time.  The next entry is in 1990, and that would be alluaivite.  Three more were accepted in 1998: they are kentbrooksite, manganokhomyakovite and oneillite.  In 1999, we add khomyakovite.  All the rest are in the 21st century. So, 20 species might be called relatively new.  Few groups can claim this status.   

Color may be one of the most interesting properties among minerals; many collectors value it above most any other trait.  I decided to try and create a list of all the colors suggested for eudialyte, the species [as presented in a number of different sources].  They are red, pink, rose-red, carmine red, cherry red, orange-red, brownish-red, orange, yellow, yellow-brown, greenish-yellow, green, violet and brown.  When I collected at Mt. St. Hilaire, there were red, pink and orange crystals which we assumed to be eudialyte.  Only occasional eudialyte group members and then perhaps only certain examples of other group members exhibit colors not already listed for eudialyte the species.  I find color to be unreliable and probably misleading in the identification of the 26 species included in this group.

The proper identification of any eudialyte group member will be a complex process. As the scientific community moves toward structural mineralogy and site occupancy for species, the mineral collector is somewhat left in the lurch.  One good aspect (if you like more species) is this: new species identifications based on structural differences have resulted in many new species being described.  In 1990, there were two species in this group; by the year 2000 we had six.  Currently, the total is up to 26 (or more) and that is worth factoring into your collecting plans.  Identifying the 26 members is a challenge; the following article will briefly describe the members and their chemistry as well as noting some important locality data.  You probably need X-ray data, site occupancy information and detailed chemical analysis to positively identify a given species in the eudialyte group.

The chemistry of eudialyte is in a word, scary or so it seems to me.  Is there a mineral group that contains about half of the elements of the periodic table besides the eudialyte group?  One reference, Khomyakov (2008) claims this to be a fact.  I can confirm at least a third of all elements are at least occasionally present in the 26 group members.  My claim is based on published analytical data from multiple sources but is not to be considered as exhaustive or necessarily complete. The difference is possibly composed partly of additional REE’s that I have not found in the references searched so far.  Based on the ideal formula (see Back, 2014), you might assume that it would be easy to separate the 26 species; I’m not so sure it will be a simple matter. In the ideal formulas as given in Back (2014) there are 18 elements plus REE and vacancy.  The total chemistry is even more complex; see table 1 below. 

Table #1    Elements in eudialyte group minerals.

Al    Ba    C    Ca    Ce    Cl    Dy    Er    F    Fe    Gd    H

Hf    K    La    Mn    Na    Nb    Nd    O    P    Pr    S    Si    

Sm    Sn    Sr    Ta    Ti    W    Y     Yb    Zr

Rastsvetaeva et al (2012) refers to “isomorphic substitutions at several structural sites”, p. 496.  The descriptive notes for the sites are non-equivalent in various sources but the version below is hopefully correct.   The N sites (there are 5) usually host Na; K, Sr, Ba, Mn, Ca, REE, Y, H3O, H2O, Ce and vacancy are also noted as possible occupants.  The four M sites may contain (M1) Ca, Mn, Na, Sr, Fe and REE.  (M2) may house Fe, Mn, Na, Zr, Ta, Ti, K, Ba and H2O.  (M3 and 4) may contain Si, S, Nb, Ti, W, Na, Ce and vacancy.  The Z site houses Zr, Ti, Nb, Al, Fe, Mn, W and vacancy.  The O’ site contains O, OH, and H2O.  The “Si” site contains Si and Al.  The X (1 and2) sites contain Cl, F, H2O, OH, CO3, SO4, AlO4, and MnO4.  Jonhsen et al (2003) states that “a wide variation in chemical composition” (p. 786) is present in the eudialyte group minerals; further he claims “the theoretical number of mineral species based on the non-silicate cations only, extends far beyond several thousands”, (p. 788).  This may turn out to be a much more difficult project than we have time to resolve.  The general formula would look like N 1-5, M 1-4, Z, Si, O’, and X but see Rocks and Minerals, Vol. 89 (2014), Rastvetaeva (2012) or Johnsen et al (2003) for more detailed information.  Also, see the site data example under the description for kentbrooksite.

Solid solutions, either complete or partial, are widespread in the eudialyte group minerals.  Examine and compare the ideal formula for zirsilite-(Ce) and carbokentbrooksite – you will find (Na,Ce) in carbokentbrooksite while zirsilite-(Ce) has (Ce,Na).  This is typical of solid solution minerals and shows relationships fairly clearly.  The names kentbrooksite and ferrokentbrooksite are considered to be the Mn and Fe analogues but you will notice another difference.  Some REE is present – but only in the ideal version of kentbrooksite.  We can speculate that a series may extend from REE bearing to REE free examples in addition to the Mn-Fe series.  Alluaivite, rich in Ti, suggests a partial series might extend toward some Zr rich (the usual state) eudialyte species.  At least a few possible new species might exist at least theoretically.  Khomyakovite, richer in iron, and mangankhomyakovite, richer in manganese, offer another example of a series.  Via multiple substitutions, several species can be considered as members of solid solutions, also called solid solution series.  Just by manipulating the Fe and Mn, in ideal formula terms, there are possibly a dozen more new species.    Occasionally, we find a eudialyte described in terms of percentages of various species.  For example, Chakrabarty et al (2012) describes hydrothermal eudialyte from Sushina as “representative of the solid solution series between kentbrooksite- taseqite-Ce-zirsilite”.  Rastsvetaeva et al (2012) states “the relative amounts of the alluaivite, eudialyte and kentbrooksite structures in rastsvetaevite are about 50, 40 and 10 % respectively” on page 495.  This is another way to describe a specimen.  As a collector, I would like to be able to label the sample as a species in common usage today.

One of the slabbed specimens that is in my collection is from Khibiny; according to RAMAN data, it is ferrokentbrooksite.  This is very interesting to me and I hope the results are accurately portraying the sample.  Associated species are lorenzenite, nepheline and aegirine.  The label claims it is from the Partomdor mine; maybe actually the Partomchorr Mt.?  The specimen is a fair match to the description given by Yakovenchuk et al. in Khibiny (2005) on page 77.   Arem indicates “faceted gems well under one carat in size have been cut from Quebec material.  They are deep red and extremely rare.”  This material is possibly from Kipawa, Quebec; however Arem indicates Mt. St. Hilaire is a source for facetable material.  I have seen cabochons and lapidary slices of eudialyte with various minerals such as lorenzenite, nepheline, aegirine and agrellite etc. from Canada and Russia, the spheres and eggs made from this material are all quite interesting and occasionally spectacular.  If you decide to buy any of this material for specimens or lapidary use, find out what it might look like and where it is said to come from.  Use the internet to help determine if photos are available and then compare the appearance and stated locality.  Choose your dealer wisely since you will probably be relying on his expertise and supply chain to be reasonably sure that you get what you expect.  As always, a fine crystal is preferable to a grain or mass if you have the choice.  Not all species will be available as nice crystals. 

Finally, a note about rare earth elements: defined in different ways, I will use the list from Wikipedia.  There are 17 REE’s: Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.  Many have been documented within various eudialyte group minerals.  Refer to Back (2014) and you will see several members of this group have REE; several more have Ce (cerium) in the ideal formula too.  At least nine species fall within this category based on the criteria given above.  

In summary, a collector faces some difficult choices when purchasing eudialyte group minerals.  From my perspective, I see many more or less massive examples that may or may not contain variable percentages of the rarer species.  Of course, a fine crystal is always a better specimen but will you lay out, say $250 or more for a sample that will be partially consumed in a more or less definitive study that may cost several hundred dollars more?  Probably, one needs chemical and structural data to be near positive of the correct identity of a given sample.  That sounds to me like it will be quite expensive and perhaps not worth your efforts.  As noted repeatedly in my brief species descriptions, there is very complex chemistry and variable amounts of components.  If one or more elements start to rise in terms of weight percent, the possibility exists that you have a different species; perhaps even a new species!  The samples themselves will often be intergrowths with two or perhaps more species present and intimately associated.  This is characteristic for this group of minerals. 

Rarity

By Bill Shelton

If we consider a crystallized well-formed example of any mineral in comparison to the bulk of the crust, it will be infinitesimally small in terms of percent.  Hence, it could be characterized as rare.  A mineral collector often has a different slant on things and may refer to rare species or rare habits; also rare from a certain locality.            

RARE: May mean distinctive or uncommon as it applies to minerals.  Similar to infrequent; also may imply choice such as the best piece.                        

Amongst various factors affecting rarity and our perception of rarity consider the following possibilities.   A rare element may greatly restrict how much of a certain mineral exists – then consider how much might actually be identified and recovered.  Then, what quantity gets into the “mineral marketplace” and ultimately becomes available to you, the collector.  Further, will you be aware of the few dealers who may have this “rarity”?  Minerals that may be considered rare on the basis of chemistry might include minerals found to contain certain rare elements, perhaps in significant quantities as seen in their formulas.  Certain rare elements, however, have quite a few commonly found minerals readily available for sale.  Rubidium, #22 in rarity, has essentially no mineral examples where it is present in much quantity because it tends to be dispersed in low amounts in other species such as the feldspar group.  Bismuth, #70 in rarity has almost 150 mineral species – a huge number for such a rare element. Bismuth can be found as a native element and in species like bismuthinite. Rarity for elements is a number from 1 to 92 based on the relative abundance in the earth’s crust.   See the 2011 Gem and Mineral Almanac Section V: Elements and mineralogy for more on this topic.

Now a real factor to deal with is the mineral marketplace.  If you can’t find a sample for sale perhaps it is simply unavailable rather than truly rare.  Maybe there are only a few examples of the mineral known to exist.  That sounds like it might be really rare.  Examples exist where a single specimen is known –they certainly qualify as rare.  A few minerals are only known from one or a few places – they may be rare but not necessarily.  Consider charoite from Russia – essentially none exists elsewhere but a collector can buy a dozen pieces at most any major mineral show – never mind online.  One locality minerals may be rare-it might be dependent on the number of pieces available for sale rather than anything else. 

If location is factored in, rarity takes on a new appearance.  Some minerals are almost never found at particular places.  They can be described as rare from that place.  A collector can go to mindat.org and get a number for each species that suggests how many places it has been recorded from.  Similarly, quality can affect our perception of rarity.  A number of minerals rarely produce very fine crystal groups even though they are common species.  These minerals, then, are rare as fine specimens.  Crystal size can also be used.  Large, perfect crystals for many species can be few and far between even for minerals that are relatively common.

A gwindel of quartz may be rare from some places but collectors generally discount quartz as a rare species due to the ready availability of ordinary specimens and the fact that it is found at so many localities.  Yet, a large, perfect gwindel will not be easy to find.  So, when you hear that something is rare, listen for an explanation.  It is my impression that “rare’ is probably overused and incorrectly applied with regard to mineral specimens.  Also, bear in mind that sellers can use the concept of rarity to influence potential buyers.  Texts in our field use the term rare in a relative sense.  For example, Dana’s Manual of Mineralogy (1971) lists rare hydrous carbonates on page 325 and includes aurichalcite.  On page 415, aegirine is said to be relatively rare.  Page 471 tells the reader pollucite is a rare isometric mineral.  Mindat.org lists 869 places for aurichalcite, 989 for aegirine and about 150 for pollucite.  Compare these to, say, diamond with 696 localities or charoite with only 9.  I would like to add that none of these is rare in the marketplace in my opinion.

Tungsten Minerals

By Bill Shelton

Few elements have alternate monikers but tungsten – “heavy stone” – may also be found as wolfram or “wolf dirt”. It was known and detected in wolframite about 250 years ago. Currently, one can find a few collectible species with considerable tungsten in their chemistry. Oliver Sacks called Nature’s Building Blocks by John Emsley (2001) “A marvel ... sheer delight.” Excerpted above, readers find a bit of Emsley’s chapter on tungsten.

In Ford, 1966 [Dana’s Textbook of Mineralogy] we find eleven species in Appendix B. Wolframite and scheelite are the two major species indicated on the list. It is noteworthy that currently we would redefine wolframite as presented by Ford, in a different manner. For example, Back, 2014 [Fleischer’s Glossary of Mineral Species] indicates wolframite is a mineral group with five species; collectors are most familiar with ferberite and hubnerite. One may consider these as a solid solution series from ferberite, the iron-rich member through hubnerite, the the manganese-rich member. Fe–Mn series are very frequently encountered in nature; this is but one example known.

The strategic importance of tungsten, particularly in relation to armor piercing weapons and armament might surprise you. An interesting historical example – “Why was Nazi Germany short of Tungsten?” – can be found at: http://forum.axishistory.com/viewtopic.php?t=163333. 

Collectors seeking fine examples of ferberite, hubnerite and scheelite will probably be pleased to note that I think they are all reasonably available at most any mineral show. And, most other tungsten species are generally classified by me as being of minor importance for a collection.

Historical perspective here might of interest: Sinkankas in 1964 [Mineralogy for Amateurs] suggested “good specimens of their compounds (molybdenum and tungsten) are relatively scarce”. Bolivia, Bohemia and Colorado were his choices for the best examples (in 1964) for wolframite group members. Scheelite is indicated from Connecticut, Utah, California and Arizona. Worldwide, we find England, Bohemia, Italy Spain, Japan and Korea. Illustrated we note a crystal from Mexico. 

More recent finds perhaps eclipse these older localities in size, quantity and even quality. Consider, if you will, ferberite from Portugal and Kazakhstan along with hubnerite from Peru. What will we think about Chinese, Russian and Pakistani scheelites found and made available in the last fifty or so years? Bernard and Hyrsl, 2004 [Minerals and their Localities] mention, in addition to the localities above, South Dakota, Germany, France, Spain, Uganda, Rwanda, Peru and Japan. For hubnerite, South Dakota, France and Montana are among their selections.

Moving to scheelite, a long list can be found with Nevada, Namibia, Uzbekistan, Brazil, Australia, Peru, Malaysia, Romania, Austria and Pakistan as well as others. One might properly conclude that these three species are in fact more available now than they were fifty years ago. On mindat.org, the number of localities given for wolframite is 1632 while scheelite has 4266. 

Locally, Trumbull, Connecticut has produced scheelite of some note as well as ferberite after scheelite. Not much else is of concern to me but the probability of additional localities is likely. Some years back, I found multiple minor occurrences of scheelite in and around the famous mine in Trumbull. 

Type Minerals

By Bill Shelton

Arizona has some fame for type minerals; there are nearly 50 that I know about.  Ajoite, from Ajo, is a good example.  Yedlinite, from Tiger, is a striking example of a rarely seen mineral.  Bideauxite, also from Tiger, is an example with rare chemistry and mostly tiny samples.  Paramelaconite is a type mineral from Bisbee.  Places like Tiger and Bisbee often produce more than one type mineral.  Papagoite is another type from Ajo.  Shattuckite is known as a type from Bisbee; surprisingly it also occurs at Ajo and San Manuel (near Tiger)!  Collectors may feel drawn to localities like these and perhaps will even collect samples of these minerals.  

What is a type locality?  This designation refers to the first place where a mineral was discovered; it also must be recorded in some text, etc. having been studied and, later, accepted by the mineral community.  Recently, that implies the IMA.  Prior to 1850, some type localities are unknown.  Also, a small percentage of minerals are known for a very long time; hence they might be entitled to a designation like “known since antiquity”.  Gold, silver, copper and lead are a few examples that are classified as native elements.  There are some other elements that belong here.  One oxide, corundum, also falls in the known since antiquity class.  Almost all minerals have a type locality – Pekov (1998) states there are 582 type minerals from the former Soviet Union.  However, only 482 type specimens exist.  Mostly we find old minerals (18th – 19th century) do not have type examples in museum collections.  The Fersman Mineralogical Museum has 385 type species while the St. Petersburg Mining Institute has 225 examples.  See Minerals First Discovered on the Territory of the former Soviet Union.  Finally and perhaps most important: a type mineral must be from the type locality. 

The type specimen(s) refer to the exact piece(s) that was originally studied – hence we might expect there is only one of perhaps a very few pieces for each species.  It is not uncommon for little pieces to be removed and sold as part of the type.  It may interest you to know that additional pieces used for revisional studies (sometimes documented as neotypes) may be included under the type specimen designation.  Commonly, collectors may have a sample of a mineral from the type locality – it clearly is similar but technically not the type mineral.  Because these pieces are much more likely to be available, a collector can amass quite a lot of examples – and they may call them type specimens. 

Definitions about type specimen mineralogy.

Holotype – a single specimen from which the original description of the mineral can be determined in whole.

Cotype – multiple specimens from which quantitative, but not necessary, data are obtained for the original mineral description.

Neotype – a new specimen for the redefinition or reexamination of a mineral when the holotype or cotypes cannot be located or, upon examination, are inadequate for study.

— Wikipedia, 4/4/2016

As an example, crocoite was originally described from the Tsvetnoi mine, Uspenskaya Mt., Beresovskoye gold deposit, Middle Urals.  This, according to Pekov, is the correct data.  We commonly see Beresov specimens for sale – they may be from the type locality or nearby.  I believe no type material exists today.  However, anyone can acquire a crocoite from this area today if they choose to do so.  

If we choose to accept a general definition, then we can have a lot of examples form some species, like crocoite.  This material has a good potential for collectors and, I believe, some scientific value.  If you know the type locality, it will be simple enough to try and find a sample of a given species.  

It can be a bit tricky to do this for some minerals.  Columbite, formerly a species and now a mineral group, is a good example.  The first material came from an area near New London, Connecticut.  Since it was redescribed, we have ferrocolumbite with the type locality of Western Australia.  Also, there is magnocolumbite with a type locality of Kuki-Lyal, Pamir, Uzbekistan (?) and manganocolumbite without a type locality given.  This is all according to Blackburn and Dennon (1997) in the Encyclopedia of Mineral Names.  I would vote for New London as the type locality for ferrocolumbite because the original piece is probably this species in modern nomenclature.  Much “columbite” in this region is properly labeled ferrocolumbite.  Dana’s New Mineralogy claims the New London locality for ferrocolumbite and indicates magnocolumbite has a type locality of Kukh-i-la, southwestern Pamir Mt., Tadzhikistan.  There is no data for a type locality for manganocolumbite. Further, Pekov confirms the magnocolumbite locality but calls the place Kukhilal gem spinel deposit, Pyandzh River valley, SW Pamir, Tadjikistan.

The Handbook of Mineralogy sometimes indicates where type material is located.  For ferrocolumbite, it is the Natural History Museum, London, England.  It is not given for the other two species.  Pekov does not tell us where the magnocolumbite type specimen is located; he indicates this information for most species in his book.  One should assume all the data is available – finding it may be a problem.  I’m still not sure where the manganocolumbite type locality is for example. 

Using mindat.org, you can see the “most prolific type localities”.  Perhaps you will find these examples interesting.  Tsumeb has 70 types and 284 species while Mt St. Hilaire (including Poudrette) has 65 types and 400 species which is the second most on this list. The Clara mine has the most at 405.  For contrast, Franklin mine indicates 36 types and 173 species and the Sterling mine has 22 types and 229 species.  Surely some listings clump Franklin and Sterling together as if it was a single place.  If you clump the Kola localities as a single entity, it will easily win and I find over 10 places on the mindat list from the Kola region. Langban, Sweden wins with 72 types and 287 species which is the highest number of types on this list.  Again, you may be frustrated; for example the list of 100 localities tells you that the Kirovskii apatite mine has 16 types and 84 minerals.  Click on the name and a detailed list comes up where it says there are 19 types and 112 valid minerals.  The Kovdor Zheleznyi mine (Iron mine) has 13 types and 55 valid minerals; it is located near the border with Finland but could be grouped with other “Kola” localities.  Pekov says that Khibiny and Lovozero (together) have 118 types as of 1997.

Bernard and Hyrsl (2004) tell us the “Richest type localities of the world” include Lovozero (90 types) with 41 from Karnasurt and 24 from Alluayv.  Khibiny has 80 with 20 from Kukisvumchorr and 21 from Yukspor.  Langban has 72; Tsumeb has 59; Franklin-Sterling Hill has 58 and Mt. St. Hilaire has 43.  So, where you choose to look may produce anomalous results.  Recent investigations can increase the total for a locality – a few places get a lot of attention; i.e. Tsumeb.  Despite some lack of agreement, it is clear that a few places, whether considered as single places or combined regions, are the most prolific in the world.  It would make sense to me to rethink the system used and look at the data in a single, unified fashion.  I would like each mine, etc. to be a single entity and this seems to be the inclination of the mindat list.  A place like Lovozero includes many individual sites and should not be considered equivalent to a single quarry site such as Mt St. Hilaire.  In any event, you now have the names of a few places that are really famous for type species and can embark on your own crusade to perhaps acquire a set of type locality samples.