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4wRe: Cuprite?Reply from Dr. Günter Grundmann in Photos.Dear Elek,Please compare the corresponding photomicrographs from the same polished section: Here you can see (with crossed polarizers) cuprite with red dispersed light internal reflections (Cpr) in association with tennantite isotropic and opaque (Tennantite Subgroup) in direct comparison next ...
4wRe: Cuprite?Reply from Dr. Günter Grundmann in Photos.Dear Elek,Please compare the corresponding photomicrographs from the same polished section: Here you can see cuprite with red dispersed light internal reflections (Cpr) in association with tennantite isotropic and opaque (Tennantite Subgroup) in direct comparison next to each other.Best ...
4wRe: Cuprite?Reply from Dr. Günter Grundmann in Photos.Dear Elek, This polished section clearly shows a secondary sulfidization process. Thank you for your attention. I'm afraid your assumption that the cuprite (Cpr) I referred to could be "tennantite" is rejected by the clearly visible optical properties: The cuprite with crossed polarizers ...
6wRe: Identity Requests (split from Branko's request for messageboard change)Reply from Dr. Günter Grundmann in General.Alfredo, Absolutely great statement! Many thanks!
8w⚠20 imagesRe: Synthetic or Man-Made mineralsReply from Dr. Günter Grundmann in General.Ed, I am convinced that you are on the right track! With your statement you encourage me to make the results of one of my research topics available on mindat.org. An international team has been researching the role of artificial arsenic sulfide pigments in cultural heritage for over 25 years. ...
8w⚠20 imagesRe: Synthetic or Man-Made mineralsReply from Dr. Günter Grundmann in General.Ed Clopton, Thank you very much, your statement underlines my thoughts perfectly!!
8w⚠20 imagesRe: Synthetic or Man-Made mineralsReply from Dr. Günter Grundmann in General.Please be very careful about the meaning and use of the terms "Man-Made", "artificial", "natural", "manufactured", "mineral", "crystalline", "amorphous", "synthetic", “growing crystals”, etc. Things are getting mixed up here! It is an extremely complex and complicated subject!
11wRe: Saline Bad Kreuznach: two entries and wrong photosReply from Dr. Günter Grundmann in Improving Mindat.org.Thank you Hartmut for your consent. I also think that the motif on the “Waschbach” card fits more into the Alpine region. But it is an authentic contemporary document that must not be deleted.
11wRe: Saline Bad Kreuznach: two entries and wrong photosReply from Dr. Günter Grundmann in Improving Mindat.org.You recognized correctly, there were some errors and confusion here. For this complex I made a few small corrections to both the locality name and the coordinates. I hope this finds your approval. Changed name and coordinates from 'Saline, Bad Kreuznach, Bad Kreuznach, Rhineland-Palatinate, ...
15wFoto of Erich Seeliger for the seeligerite pagePosted by Dr. Günter Grundmann in Improving Mindat.org.Here is finally a photo of Erich Seeliger, Professor of Mineralogy, Technical University Berlin, Germany, for the seeligerite page. Photo taken in 1967 at the Johannesschacht Mine, Wölsendorf, by Dr. Heinz Ziehr, Mainz.seeligerite named after Prof. Dr. Erich Seeliger, Professor of Mineralogy, ...
15wRe: Perth, Western AustraliaReply from Dr. Günter Grundmann in Identity Help.Agree - it is a strongly foliated, low grade metamorphic granitic augen gneiss, with predominantly K-feldspar megacrysts.
Jan 2024Re: Oncolite instead of "pisolite"Reply from Dr. Günter Grundmann in Photos.Key points when distinguishing between “pisolite” and “oncolite” are: The components of the pisolites (pisoide, peastone, pea grit) are generally of terrestrial origin in the freshwater environment, and have a uniform size of the components, please compare Karlsbad peastone.The components ...
Jan 2024Re: Oncolite instead of "pisolite"Reply from Dr. Günter Grundmann in Photos.John and Franz,First of all, I didn't use the terms "pisoids" or "oncoids", but instead the term "pisolite". It is with embarrassing horror that I see your contempt for my recommendation. Geology is neither a dice game nor a “play of devil’s advocate”. Please respect the definitions in the ...
15wOncolite instead of "pisolite"Posted by Dr. Günter Grundmann in Photos.May I recommend that this very nice and typical specimen should be renamed from "pisolite" to "oncolite". Many thanks,Günter Grundmann
Jan 2024Re: Fireworks display of lepidolite - 2024Reply from Dr. Günter Grundmann in General.Steve,No problem at all, good idea!You are welcome!
Jan 2024Fireworks display of lepidolite - 2024Posted by Dr. Günter Grundmann in General.Happy New Year to All
Dec 2023Merry Christmas and a Happy New Year!Posted by Dr. Günter Grundmann in General.This is a hundred and twenty year old artist, multicolor, gold-printed, embossed lithograph postcard; artist, photographer and publisher unknown. Thank you to everyone at mindat.org!
Dec 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.This is the panoramic view of the quarry just 8 years later! The “Basaltsteinbruch Bennauerkopf” basalt quarry, in 1909. Vintage picture postcard, photographer P. Siebrighausen, Asbach/W. The card was sent on 2 September 1909 from Asbach to Detmold. G. Grundmann collection.
Dec 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.Another from Neuwied, Rhineland-Palatinate, Germany. The “Basaltsteinbruch Bennaukopf” basalt quarry, in 1901. Vintage picture postcard (“ Serie II. Brölthaler-Eisenbahn. AK No. 9”), photographer Rudolf Stolle, Bad Harzburg. G. Grundmann collection.
Dec 2023Re: Biehlite - Friedrich Karl Biehl (1887 - ?) - more info & photo?Reply from Dr. Günter Grundmann in Improving Mindat.org.The "Internationaler Geologen- und Mineralogen-Kalender 1937" published by the Deutsche Geologische Gesellschaft Berlin, edited by Dr. Edmund Beyenburg, Ferdinand Enke Verlag Stuttgart, provides proof of Dr. Karl Biehl: In 1937 he was "Leiter des Forschungsinstituts der Tuffstein- und ...
Dec 2023"spray of bismutite crystals"?Posted by Dr. Günter Grundmann in Photos.Isn't the "spray of bismutite crystals" actually a spray of bismuthinite crystals?
Dec 2023Re: Carmen Mine, La Union, Los Andes Province, La Paz, BoliviaReply from Dr. Günter Grundmann in Localities.Uwe,According to the paper by Friedrich Ahlfeld (1932): "Die Erzlagerstätten in der tertiären Magmenprovinz der Bolivianischen Zentralanden." In: Sonder-Abdruck aus dem Neuen Jahrbuch für Mineralogie etc. Beil.-Bd. 65. Abt. A. 1932. S. 285-456. is the "Grube Carmen. Zinnsteingänge mit Wismut. ...
Nov 2023Re: Would you be interested in voting for a POTM ?Reply from Dr. Günter Grundmann in General.Franz, I'm sorry that I misunderstood your statement. I just wanted to draw attention to the extremely low interest in "run-of-the-mill ore samples" in mindat.org.
Nov 2023Re: Would you be interested in voting for a POTM ?Reply from Dr. Günter Grundmann in General.Eddy, I'm sorry that I misunderstood Franz Bernhard's statement. I just wanted to draw attention to the extremely low interest in "run-of-the-mill ore samples" in mindat.org.
Nov 2023Re: Would you be interested in voting for a POTM ?Reply from Dr. Günter Grundmann in General.Sorry, but the term “ore geology” you used does not exist (at least in the Glossary of Geology, Second Edition by Bates and Jackson, 1980). And your disdain and contempt for “run-of-the-mill ore specimens”, after 18 years as a user of mindat.org, is just embarrassing. Ore minerals are ...
Nov 2023Re: Would you be interested in voting for a POTM ?Reply from Dr. Günter Grundmann in General.Behind every form of competition there is always hidden envy, resentment, jealousy, showing off and arrogance. And these unpleasant human characteristics must never spread in mindat.org!
Nov 2023Re: Minerals in ArtReply from Dr. Günter Grundmann in Improving Mindat.org.May I repeat my question from August 20th, 2021, regarding the unique, 100-year-old postcard series (Drawings by F. R. Mold) from the British Museum (Natural History). Picture Postcards from the British Museum (Natural History) - How to contribute Almost a hundred years ago the British Museum ...
Oct 2023Re: NeudorfReply from Dr. Günter Grundmann in Field Collecting.According to the book by Wilfried Ließmann "Historischer Bergbau im Harz – Ein Kurzführer", Schriften des Mineralogischen Museums der Universität Hamburg, Band 1, Editor Dr. Jochen Schlüter, Verlag Sven von Loga, Köln 1992, the Pfaffenberg mine („Schacht ...
Oct 2023Re: NentershausenReply from Dr. Günter Grundmann in Improving Mindat.org.Please find attached the geological scetch map of the Richelsdorf mountain ridge with the position of ore veins and important old mines and shafts, according to Stoppel & Gundlach (1983), in “SCHNORRER-KOEHLER, G., (1984), Die Minerale des Richelsdorfer Gebirges 1. ...
Sep 2023Incorrect specimen dimensions?Posted by Dr. Günter Grundmann in Photos.Compared to the weight of the specimen of 100 g, the dimensions should not be given in millimeters but in centimeters. Either way, very nice specimen!
Sep 2023Re: Incorrect location is assignedReply from Dr. Günter Grundmann in Photos.Uwe,Many thanks for your information. Changing my originally correct locality information was either a bad joke or sabotage!
Sep 2023⚠54 imagesRe: Share your mineral memes!Reply from Dr. Günter Grundmann in General.Dalesologies
Sep 2023⚠54 imagesRe: Share your mineral memes!Reply from Dr. Günter Grundmann in General.The tools that guy is sporting are actually a joke! A single powerful hit with the huge sledgehammer -- and the "chisel" with the wooden handle is no longer a chisel but a crushed piece of scrap metal. Cheers, Günter
Sep 2023⚠54 imagesRe: Share your mineral memes!Reply from Dr. Günter Grundmann in General."Big quarry." 29 September 1910.
Sep 2023⚠54 imagesRe: Share your mineral memes!Reply from Dr. Günter Grundmann in General.Over 100 years ago .......
Aug 2023Re: Be-bearing gneisses?Reply from Dr. Günter Grundmann in General.Please read the following book:Reviews in Mineralogy & Geochemistry, Volume 50: Beryllium - Mineralogy, Petrology and Geochemistry.- By Edward S. Grew, Editor. Mineralogical Society of America, Paul H. Ribbe, Series Editor. Geochemical Society Jodi J. Rosso, Series Editor.ISSN 1529-6466
Aug 2023Re: No natural crystalline orpiment!Reply from Dr. Günter Grundmann in Photos.Alfredo,you are right, the other superb photo https://www.mindat.org/photo-1314929.htmlshows the same phenomenon.
Aug 2023No natural crystalline orpiment!Posted by Dr. Günter Grundmann in Photos.No natural crystalline orpiment! This image does not show natural crystalline orpiment, but instead artificially generated x-ray amorphous "resinous" orpiment glass on the surface of the specimen! Please read our publication on this extremely complicated topic: ...
Aug 2023Re: Orpiment or pararealgarReply from Dr. Günter Grundmann in Identity Help.The distinction between realgar, pararealgar and orpiment. This photograph (sorry, partially blurry) is intended to distinguish fragments of the arsenic sulphide realgar, pararealgar and orpiment from the Getchell Mine. Realgar can be identified by its red color. Pararealgar can be identified by ...
Aug 2023Re: Orpiment or pararealgarReply from Dr. Günter Grundmann in Identity Help.The distinction between realgar, pararealgar and orpiment. This photograph (sorry, partially blurry) is intended to distinguish the intergrown arsenic sulphides realgar, pararealgar and orpiment on the fracture surface of a specimen from the Getchell Mine. Realgar can be identified by its red ...
Aug 2023Re: Orpiment or pararealgarReply from Dr. Günter Grundmann in Identity Help.The simplest way to distinguish orpiment and pararealgar is the pin method: A pinprick on the surface of pararealgar shows brittle deformation with angular fragments, orpiment shows ductile deformation with bending and delamination of the layer-lattice structure similar to graphite or molybdenite. ...
Aug 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.Greetings from Tasmania! The columnar basalt cliff at Cape Raoul.
Aug 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.Greetings from Iceland! The Svartifoss waterfall, 20 m high, with columnar basalt cliff.
Aug 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.Greeting from Giant's Causeway!
Jul 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.Ed,... and here is another one! All this can be found in the gigantic treasure chest mindat.org!
Jul 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.Hi Ed,How about this basalt fan?
Jul 2023⚠44 imagesRe: Fabulous columnar basalt!Reply from Dr. Günter Grundmann in Photos.https://www.mindat.org/photo-920417.htmlAnd what do you think of this one?
Jul 2023Re: Help/suggestions translating BesucherbergwerkReply from Dr. Günter Grundmann in Education.Alfredo, The online dictionary "LEO" dict.leo.org/englisch-deutsch contains over 80 different explanations related to the term "tourist". The word "Besucher" does not appear anywhere in these explanations and descriptions. When translating the term "Besucher", the word "tourist" does not ...
Jul 2023Re: Help/suggestions translating BesucherbergwerkReply from Dr. Günter Grundmann in Education.I understand the term "tourist mine" as generally derogatory. A mine that is open to the public does not have "tourists" but visitors! From this it follows crystal clear for me a "Besucherbergwerk" is a visitor's mine. I haven't seen any mine referred to as a "tourist mine", too!
Jul 2023Re: Help/suggestions translating BesucherbergwerkReply from Dr. Günter Grundmann in Education.visitor's mine
