Rare Mineral Species |
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| Rare Species. We have them! | |||||||
The term rare species refers to rare or exceedingly rare minerals. There are almost always very unspectacular, and are usually valued by researchers and those wanting them for special reasons like to build an extensive collection. Very often rare species occupy only a very small portion of the piece... with the result that most of the specimen is only matrix! Rare species are important mineralogically for various reasons one of which is that they account for quite a high percentage of known minerals. We may also mention that most new minerals discovered these days are rare species: in most instances one can say that if they were not as rare as they are, they would have probably been found a long time ago. Now let's be clear: we love to photograph minerals and show them off but we have to admit that usually rare species are photogenically a hopeless case! So we will usually just list them and if you have questions we will try to answer them. So Enjoy! Here are some Uglies! Actually a few, VERY FEW, are pretty. E-mail us attard@attminerals.com |
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argyrodite Freiberg extremely rare Ag-Ge-sulphide (pure piece from an original find in the 1880's sold out but may get more: enquire....see bottom re this) cheralite, massive, big piece, X-rayed $50 chiavennite - rare, orange crust $40 churchite - white fibrous, formerly known as weinschenkite from this locality $36 cobaltkoritnigite - pink balls, rich $70 gehlenite - white massive, ugly $25 hartite - new find described in Amer.Mineralogist (1999), white massive similar to gypsum $30 jeromite: red crust on quartz, first natural occurrence (original was from a mine fire) $40 lithiophyllite - greenish gray massive, rich $30 lomonossovite - brown crystals in matrix $30 loparite - nice twinned crystals $40 lotharmayerite - extremely rare, type locality, small red-brown crystals (nice in microscope), with adamite $100 pearceite - nice metallic crystals with white stilbite, some people describe it as arsenpolybasite but both X-ray and XRF on this material show it to be pearceite ! $50 parisite - big crystals, pure, from a classic locality $55 paulingite-Ca - nice big crystal $35 Platinum, Russia- 2 mm cube with X- ray spectrum and SEM, sold out but enquire as we may get more. sodium-zippeite - yellow on matrix $38 steenstrupine - big black grains with serandite etc., radioactive $40 terskite - gray massive, strong green fluorescence, with purple eudialyte $38 umangite - metalic on matrix, Russia $60 sold out but enquire if interested : we may get more zavaritskite - gray grain in quartz, pseudo after native Bi $48
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NOW is any of this interesting? Well not to everyone but consider this on just one mineral: Regarding Argyrodite, it is of historic importance because in it the element Germanium was discovered. If one were to digress a little on Germanium, one may add that it had been predicted by the young British chemist Newlands in 1864 as the missing element in a triad between Silicon and Tin. Seven years later the much older Russian Mendelev specified the properties it should have using his newly devised Periodic Table of the Elements. A hunt got under way by inorganic chemists and to be brief, in 1886 Winkler found it and named in honor of his country. The source was Argyrodite. Lest it be thought that this was a straightforward process, one might mention that Winkler having isolated it, nevertheless assigned it the wrong place among the then missing elements! It was not untill some time later that another German chemist Lothar Mayer (now of Latharmayerite fame) recognised its proper identity and position in the Periodic Table that the case on Germanium was finally concluded. Now you know a little more about Argyrodite! From knowlege comes appreciation. |