Obnova členství/Renewal of membership

*English version see below

Kvůli pandemii COVID-19 členské příspěvky letos nebudeme vybírat na vánočním večírku (žádný se konat nebude). Členské příspěvky nám zašlete na účet a to nejpozději do 30.12.2020. Do zprávy pro příjemce pak vyplňte své jméno (pokud jméno nevyplníte, peníze propadnou do pokladny SGA). Vzor viz níže.

Due to pandemic situation we are not able to take out money for prolonging your membership on christmass party (there won´t be any). Send us your membership fee on our bank account (pattern see below) by 30.12.2020. Into the message for receiver fill your name (in the case you won´t do so, money money will be added to SGA account).


  • účet/account: 2058839019/3030
  • cena/price: 260 Kč (10 Euro)
  • zpráva pro příjemce/message for receiver: Vaše jméno/Your name
  • do/by 30.12.20 !!!

Nejste ještě členy SGA? Přidejte se k nám! Stačí vyplňenou přihlášku poslat našemu prezidentovi na email (jaromers@natur.cuni.cz) a zároveň poslat členský příspěvek na již zmíněný bankovní účet.

You are not a member of SGA? Join us now! Send filled application to our president on email (jaromers@natur.cuni.cz) and send membership fee on already mentioned bank account.

Přihláška pro zájemce/Application form for new members:

Moldavites of South Bohemia

Štěpán Jaroměřský; Karolína Fizková; Jan Šulc; Štěpán Dvořák; Marek Tuhý

Faculty of Science, Charles University, 128 43 Praha 2, Czech Republic; Corresponding author E-mail address: jaromers@natur.cuni.cz

Fig. 1: Ongoing lecture; Photo by Štěpán Jaroměřský

On 30th July was organized, despite some restrictions caused by the pandemic, excursion to South Bohemia. 15 Chapter members took part in this 1-day excursion. The expert interpretation was led by Mgr. Miloš Faltus, Ph.D. (Fig. 1). The aim of the excursion was to introduce the participants to the Czech rarity in the form of tectite called Moldavite. As one of the few people we were given the opportunity to look into the sand pit (Fig. 2), which is located between the village of Chlum and Ločenice. This sand pit is mainly used for sand mining, but its secondary product are the Moldavites (Fig. 3). It is the only company in the Czech Republic that has permission to officially mine and then sell Moldavites

Fig. 2: View of the sandpit; Photo by Jan Šulc
Fig. 3: Active treatment plant; Photo by Jan Šulc

The first discovery of Moldavites was in 1787 by Dr. Josef Mayer from Charles University. He had thought of them as glass of volcanic origin. They were named after the Vltava River, around which the first findings were located. Later, the concept of Moldavite was introduced from German Moldau (Vltava). As similar glasses were later found more widely around the world, the common international name of tectite (from Greek tectose – fused) was also used for them. Generally they are vitreous bodies, which usually have dimensions of several centimeters and a weight of several units up to tens of grams. Tectites can be found all over the world, but Czech Moldavites, unlike others, have a transparent light or dark green colour.

Today, the most likely and widely accepted theory of the formation of Moldavites is considered to be the impact of a meteorite on the surface of the Earth some 14.5 million years ago. This impact occurred in the area of today’s so-called The Ries crater between Norimberk, Stuttgart and Munich. Today in the centre of this crater lies the city of Nördlingen. The Ries crater is 24 km in diameter. The meteorite impact occurred at a speed of about 20 km/s, at an impact angle of 30-50 °. During the collision with the Earth, a huge amount of energy was transferred, resulting in the crushing, melting and evaporation of rocks at the point of impact as well as a separate cosmic body. There was a cloud containing gaseous, liquid and solid phases, the main part of which was directed to the East. When the initial high temperature and pressure dropped, the silicate melt solidified so quickly that the individual mineral components did not fully crystallize to form silicate glass. This was particularly the case in the area of southern Bohemia and southern Moravia in the vicinity of Trebic. The range of the vltavins from Ries crater to southern Bohemia and southern Moravia was 200-450 km. It is estimated that the total weight of all fallen vltavins would be about 3000 tonnes.

Fig. 4: Currently found moldavite; Photo by Jan Šulc

South Bohemian Moldavite is characterised by its light – dark green colour. This is different from the Moravian ones, which tend to be in brown colours. Very rarely was also discovered bicolor moldavites, probably due to the combination of two distinct moltens before impact. Chemically, it is silicate glass, except for SiO2, which is 70-80 % represented in moltens, we can find Al2O3 in the composition. MgO, CaO or Fe oxides. The hardness varies between 6 and 7 of Mohs scale

Macroscopically, they have a very peculiar appearance and they are mostly in the shape of balls, sticks, droplets, also rarely for heart or hedgehog shapes (Fig. 5). A great interest is the sculpture, which occurs mainly on the Moldavites from southern Bohemia. This is the name of the surface of the individual samples, which has been disturbed by the acids contained in the soils. These acids then stick to the surface of the Moldavite over time, resulting in a certain wrinkling of the surface, which is quite valued. Moldavites also contain a number of inclusions, which take the form of closed-gas bubbles. Because the Moldavite is chemically very close to the glass, it is sometimes difficult to distinguish the cutted Moldavite from the cutted green glass.

Fig. 5: Rare hedgehog Moldavite form; Taken over: http://observatory.cz/static/vystavy/vltaviny/4-vltaviny.php

The sand pit, which we visited as part of our excursion, belongs geologically to the South Bohemian basins, where sedimentation began during the Cretaceous period and continued until the Tertiary. The basins are composed primarily of fluvial and lake sediments. In the visited sand pit we find Moldavites in the Domanín formation, in the Korosec series, in sands to gravel with clay inserts. Moldavites are a rare mineral, and a lot of people want them to make money. In most cases, they dig even a few meters deep pits (Fig. 6) to get into the layers that contain the Moldavites. Unfortunately, this intervention often destroys nature, natural root systems and endangers animal safety. This problem has been solved for several years and is likely to be solved by extracting all layers with Moldavite findings (except fields) followed by rehabilitation to the original natural conditions.

Fig. 6: Consequences of illegal mining; Photo by Jan Šulc

The whole excursion was a great success and we would like to thank the owner of the sand pit Ing. Viktor Weiss, who allowed us to enter the normally inaccessible area. We would also like to thank Mgr. Miloš Faltus, Ph.D., who gave us a professional lecture and last but not least, we would like to thank the entire SGA for our long-standing support and favor

  • Baier, J. (2009). Zur Herkunft und Bedeutung der Ries-Auswurfprodukte für den Impakt-Mechanismus. Jahresberichte und Mitteilungen des Oberrheinischen Geologischen Vereins, 9-29.
  • Baier, J. (2007). Die Auswurfprodukte des Ries-Impakts, Deutschland. Verlag Documenta Naturae.
  • Vand, V. (2009). O původu tektitů a vltavínů. Pokroky matematiky, fyziky a astronomie, 54(1), 23-32.
  • Řanda, Z., Mizera, J., Frána, J., & Kučera, J. (2008). Geochemical characterization of moldavites from a new locality, the Cheb Basin, Czech Republic. Meteoritics & Planetary Science, 43(3), 461-477.
  • Skála, R., Strnad, L., McCammon, C., & Čada, M. (2009). Moldavites from the Cheb Basin, Czech Republic. Geochimica et Cosmochimica Acta, 73(4), 1145-1179.

Prague SGA Student Chapter visiting Columbia-Bogotá SGA Student Chapter: Mineral deposits of Columbia

Štěpán Jaroměřský, Ivan Mateo Espinel Pachón, Jan Hofmann, Milton A. Santos

1SGA Student Chapter Prague, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic; jaromers@natur.cuni.cz

Photo of the whole group of participating members

As every year, Prague Chapter participates in several fieldtrips with friendly chapters. This year, we managed to negotiate several daily fieldtrips with the SGA Student Chapter Columbia-Bogotá, which should have focused on emerald and gold deposits. The main target was to visit the world famous emerald deposit near the town of Muzo. However, the whole program was charged and very well prepared by the Colombia-Bogotá Chapter. The Prague chapter was represented by 10 members and the field trip lasted from March 19 to 25.

1st day:

On the first day we visited a sedimentary-exhaliative deposit (SedEx) near Chiquinquirá – Boyaca. Sedex are ore deposits formed by a release of ore-bearing hydrothermal fluids. Subsequently, they must be released into a water reservoir, resulting in the precipitation of stratiform ore. SedEx deposits are the most important sources of lead, zinc and barite. These ores are processed for tungsten, copper, silver, gold and bismuth.

This deposit is located high in the mountains of northern side of central Colombia. 10-year-old exploration galleries designated for researching copper in the past surround the site. There are abundantly chalky sediments, in which there are minerals of copper such as chalcopyrite. We also found some beautiful examples of barite crystals. It is a fairly extensive site, but because of the steep slope and dense fog, we stayed on the upper parts of this deposit. It was a nice introduction to Colombian geology and nature.

2nd day:

On the second day, our emerald trip started in Las Pavas area. We had accommodation in the town of Muzo, from where a very narrow path led through the local mountains. Muzo itself is well known for its emerald deposits.

Emeralds are usually found in calcite-dolomitic veins containing pyrite, ankerite, albite and quartz. These veins are the product of hydro-thermal fluids that disrupt the rock massif and the interactions of the metasomatic fluid with subsequent deposition in the breaks formed by these calcite-dolomitic veins. It is likely that metasomatic fluids come from shale formations near Muzo, which are probably the source of vanadium, which is the cause of the unique color of local emeralds.

Firstly, we headed to the Rio Magdalena where we could find some samples in the river or meander scrolls. Only one member of our chapter was lucky enough to find a small sample in the shale. We even investigated one closed mine which might be reopened in the near future.

Fine emeralds crystals from Muzo. Photo by E. Vrňatová

3rd day:

On the third day, we had a scheduled visit to El Líbano Tolima, the El Porvenir gold mine, orogenic and epithermal gold deposit. This mine is processing sulphide ores like pyrit, containing relatively large amounts of gold (up to 1000 ppm). The grains of gold in the bearing are mainly included in sulphides and silicates. The mineralization of gold in the bearing is probably caused by the penetration of porphyres into the Paleozoic slate on the eastern wing of Colombian Andes. It is believed that the mineralization of gold occurred in three early phases of intrusion, which are accompanied by a number of sodo-calcical changes and the late phase of penetration of porphyres. The samples contained high quartz and chalcopyrite content.

We travelled to the mine a long way on a car’s hull. Then we went through the inspection, which was waiting for us in front of mine. The whole mine is active and so we could only be there in the pause period. The whole visit was fantastic and very engaging. At the end, everyone could take only one sample of the size of a fist.

One of the eight entrace to the El Porvenir gold mine

4th day:

On the fourth day, we visited the Cu-skarn Payandé deposit with garnets.

The post-Triasic plutonic rocks, known as the Payande Stock, grow on the eastern edge of Colombian central Cordillery near San Luis-Tolima. The quarry could not be reached directly by our bus, so we had to stretched our legs. At least we were accompanied by a car that eased us from our backpacks and hammers. The road was not difficult, except from the ford across the river, where we had to take off our shoes and wade.

The reason why we drove there were skarn outcrops, where the great and beautiful crystals of andradite are located. Regarding the other minerals, hematite, azurite, quartz, calcite, chlorite, magnetite and sphalerite are also found here. Petrology and mineralogy is very interesting in this deposit, as there are signs of a passage of hydrothermal fluids and changing contacts with individual minerals. We saw the beautiful mineralization of the copper. There are also several zones to see. The first zone corresponds to the tonalites, the second to endoskarns and the third to exoskarns. There is also a prograde zone containing garnets and pyroxenes. In the retrograde zone, where iron oxides, iron sulphates and copper are found. This was our last locality in terrain.

5th day:

On the fifth day we were back in Bogóta and we had a planned tour of the geological section at the Universidad Nacional de Colombia. We went through some local classrooms and looked at a few samples from the local collections. We also examined a few rocks which we saw during the fieldtrip under a microscope and finally we listened to short presentations from Prague Chapter and Bogota Chapter. After exploring the area, we went to the city to taste a bit of all possible and impossible fruits on the world-famous market Plaza de Paloquemao. Then we moved to the Gold Museum in Bogota and the largest Emerald museum in the world. Unfortunately, this day the Emerald Museum was closed in, so we had to visited another day.

Finally, we would like to thank all the leaders of this fieldtrip, especially Ivan Mateo Espinel Pachón and all the SGA Student Chapter Columbia-Bogotá members for an amazing organization and for ensuring everything needed for the success of fieldtrip. In general, I think that the cooperation between Chapters is the best form of studying. Also I would like to express great thanks to the whole SGA, as it would not be organized without their support and many thanks to all our sponsors, such as Vitana or Severočeská doly.

I think that this fieldtrip to Columbia strengthened the connection between our SGA student chapters and we hope that despite the distance between Prague and Colombia we will continue to collaborate and exchange experiences.

Tasting of Colombian fruit delicacies by J. Bašus

Traditional autumn field trip: Various metal, precious stone and heritage stone deposits of central and east Slovakia

1 st day: Dřínová quarry (duplex structure with nice samples of barites in limestones) and visit of mineralogical exposition in gallery Patriot in Tišnov.
2 nd day: Špania Dolina area in the central Slovakia (heap with celestines samples, Piesky locality with azurite samples and Richtarova loc. which is type locality for deviline) and visit of Dobšiná with ongoing research of Ni and Co deposits.
3 rd day: Gretla (spekularite and goethite deposit), Novoveska huta (heap Bartolomejka with tyrolite and other Cu secondary minerals) and mine Josef close to Dubnik, where is gem quality opal deposit.
4 th day: open pit mine Fintice close to Přerov (andesites with zeolite samples)
Leader: Bc. Jakub Mysliveček (Czech Geological Survey)

photo by Ľubomír Kyrc

photo by Ľubomír Kyrc

Gold Short Course 2018 (Prof. David I. Groves)

  We would like to thank you all for participation at two-day Gold Short Course by Prof. David I. Groves and we are looking forward seeing you again! Please find our online gallery with photos from short course and post-course field trip.



Link for downloading the presentation slides here (repaired)

We would like to invite you to a two-day Gold Short Course by Prof. David I. Growes from the Centre for Exploration Targeting, UWA, Australia. The course will take place on the 19th-20th May 2018 in the building of the Faculty of Science, Charles University in Prague, Albertov 6. The ice-breaker is planned for the evening of 18th May (Friday), start at 5 pm. Attendance on the short course is for free thanks to SGA Educational Fund, but the field trip is charged by 160 EUR for SGA members and 280 for non-members.

  For any question about the Gold Short Course please contact us on gold.course.prague@gmail.com. Registration form for Gold Short Course and information about our post-short course field trip please find in the links below.

Please send your registrations on the email above. (In case of not responding please try to contact us on our personal emails).


Schedule of Gold Short Course



Before 9 am: morning coffee

9:00- 1st lecture: Introduction to orogenic gold

10:35- coffee break

10:55- 2nd lecture: The crustal continuum and genetic models for orogenic gold

12:30- lunch time

14:30- 3rd lecture: Critical factors controlling the formation of orogenic gold

16:05- coffee break

16:25- 4th lecture: Exploration targeting for orogenic gold

18:00- expected end of the Saturday program




Before 9 am: morning coffee

9:00- 5th lecture: Introduction to intrusion-related gold deposits (IRGDs)

10:35- coffee break

10:55- 6th lecture: Nature of hybrid magmas and genesis of IRGDs

12:30- lunch time

14:30- 7th lecture: Carlin-type gold deposits of Nevada and China

16:05- coffee break

16:25- 8th lecture: Iron-oxide copper-gold deposits: nature and genesis

18:00- expected end of the Sunday program

*Cancelling with refund is possible only until two weeks before each trip.
**Organizers reserve the right to cancel a field trip for lack of participants.
***Besides Icebreaker party and coffee breaks, food and drink is not provided by the organizers of the Shortcourse.

Guide: Transport, dining, etc.

Registration form for the Gold Short Course and field trip

Informations about our post-Short Course field trip

Articles about the issue to see beforehand- Gold Short Course files:

GSF Giant Gold Provinces
Lithos Paper
Hronsky et al. Paper MIDE-S-11-00118[1]
GSF-D-17-00399. Jiaodong. pdf
GSF Kalgoorlie Vielreicher

Field trip to the central part of Krušné hory Mts. (Erzgebirge)

This two day field trip took place from 3th to 4th of June 2017 and was concipated to visit mainly Fe, Mn and fluorite deposits in the central part of Krušné hory Mts. (Erzgebirge) with some additional stops on other deposits.

First day:


We started the excursion in town Horní Blatná. Here we visited vein of Marie Terezie and heap of Concordia adit . Minerals occurring there were mostly Mn ore – pyroluzite. We found also quartz in small crystals up to 3 mm. Then we moved to „Ametystová Halže“ near Horní Halže village. This site is old mining part of Měděnec district and there is a large number of surface exposure of old mining activity. We found mostly amethyst and quartz crystals, ordinarily in clusters up to 7 cm and the primary Fe ores like limonite and pyrite.


After first part of the excursion we moved to rock formation called „Sphings“ near town Měděnec formed by very high pressure deformed „eyes-schist“ from Variscian orogeny processes.

DSCN4446From this place we could see landscape of Doupovské hory volcanic centre. Our another stop was at Mědník hill near town Měděnec. This small hill is the skarn body preparated by erosion in Quaternary and one of the most mined Fe and Cu deposit in early modern age. We ascended to the top of the hill around old skarn heaps and there was lecture about local mining from medieval to the end of 20th century.

Second day:

DSCN4502The weather condition did not allow us to see all three fluorite deposits in Krušné hory Mts. according to former plan, but only Hradiště fluorite deposit near Kadaň town and Kláštěrec nad Ohří town. This small deposit was mined for barite, fluorite and hematite. We found only fluorite and hematite samples. After that we moved to The Chateau at Klášterec nad Ohří town, where was also an exhibition of local minerals. We saw very nice samples of polished agates from Horní Halže village, Černý Potok vil., Ciboušov vil. and other sites.


After that we visited local spa area and we drank local hydrothermal water from the spring. P1270149This hydrothermal energy is caused by volcanic activity bound on Ohře rift and was formed mostly in Tertiary. Then we moved to quick visit of Ahníkov (former vil.) – site with minerals of weathering of laterites. We found specific minerals like white and purple chalcedone, green chryzotile and small crystals of quartz. After that we moved to our last site which was Lehnschafter adit in Mikulov town. Mikulov was mined mostly for Ag ores like Ag-rich galenite.


Eight Chapter members paticipated on this excurstion led by Bc. Jakub Mysliveček.

For more photos please visit this link.

Field trip to the historical mining in Kutná hora and its surroundings


First day:

Visiting of adit St. Jiří in Oselské district – Medieval adit St. Jiří is a part of the mining-historical exhibition of the Czech Museum of Silver. This adit was discovered in 1967 during a hydrogeological survey and the length of its accessible part is about 280 metres.
Quarry Práchovna – A new outdoor geological exposition was opened in August 2014 in the former quarry Práchovna. In this exposition are used a blocks of rocks from Kutná Hora area, Kolín and Chrudim with thematically structured panels.

P1260547The slag heaps – were deposited in the immediate vicinity of the silver smelter. The ironworks in the Vrchlice Valley were in operation from the 15th century until the end of the 18th century. This despite of the partialy flattened heaps, containing an estimated 400,000 tons of slag, are witnesses of the vast range of medieval metallurgical activity in the area.
The St. Antonín Paduánský – is one of the most important mineralogical sites of the Kutná Hora region. The work followed a vein with a high content of antimony and silver ores. In the adit and in the dump we can get to know not only with typical veined minerals, but also with some luck we find rare silver ores. Our findings: berthierite, kutnohorite, pyrite, cave pearls.
The site of the former RD Kutná Hora establishment – here is the Turkaňk mine, which draws the mined water treated in the built-up cleaner for user quality. A large basin in the southern part of the Turkaňk zone was created by the mines collapse in 1969. In the eastern wall of the basin is a gallery of an old mine about 100 m long. This old gallery belongs to the oldest phase of Kutná Hora mining.


Old heaps after mining of ores in the village of Kaňk – This dumps are an interesting occurrence of rare arsenic minerals. For the last two years, heaps have been involved in many pitfalls because they have been exposed to erosion or by targeting of the collectors. Hopefully, due to the timely intervention of the experts which was made, there will be no complete disposal of the heaps, as was previously thought. Our Findings: bukovskite, kaňkite.

Second day:

P1260684Malešov – a magnetite rich rock deposit opened by deep mines. Our findings: magnetite, garnet, pyroxene, amphibole, prehnite, calcite, epidote.
Markovice – active amphibolite quarry near Čáslav. Known occurrences of alpine type minerals. Our Findings: prehnite, titanite, albite, calcite.
Kožlí near Ledeč nad Sázavou – a small fluorite deposit with a high content of quartz. Our findings: fluorite, quartz.

Fourteen Chapter members participated on this excursion led by Mgr. Jan Bubal.
For more photos please visit this link.

The International Raw Materials Career Days in Krakow

EIT RawMaterials, with the AGH University of Science & Technology in Krakow, and their affiliate IATI (the Institute Freeway of Technology and Innovation) would like to warmly invite you to attend the International Raw Materials Career Days in Krakow, Poland on May 21-24, 2017, for which admission is free.

The main event of the International Raw Materials Career Days will be the Raw Materials Careers Fair on Tuesday May 23, which will have as exhibitors leading European companies of the raw materials sector, spanning the full value chain of raw materials, including Boliden, DMT, BASF, KGHM, Mine Master, ZGH Boleslaw, and several others. The event will be attended by graduate students and alumni from over 15 world-class technical universities with strengths in the raw materials sector, from Poland, Germany, Austria, Czech Republic, Slovakia, Hungary, Ukraine, Sweden, and Finland, and will be open to the public and independent professionals.

Venue: foyer of A-0 building of the AGH University of Science & Technology in Krakow, located at Aleja Adama Mickiewicza 30, in the city center.

Time: May 23, 9:00 a.m. – 5:00 p.m. Sunday 21 May (12:00 a.m. – 5:00 pm, A-0 building of AGH University) – Short Course in Geochemical Exploration offered by Dr. Denis Schlatter, EurGeol, PhD, CEO of Helvetica Exploration Services from Switzerland (open to students only, full details to be circulated shortly).

Monday 22 May (9:00 a.m. – 5:00 p.m.) – Continuation of the short course.

Tuesday 23 May (9:00 a.m. – 5:00 p.m.) – Raw Materials Careers Fair.

Tuesday 23 May (11:30 a.m. – 5:00 p.m., A-0 building of AGH University) – Conference: ‘Raw Materials in the Polish Economy’ with presentations by the Chief Geologist of the Country, Secretary of State, Prof. Mariusz Orion-Jędrysek, as well as other senior government speakers and the managers of leading Polish raw material sector companies, including KGHM, ZGH Boleslaw, PGNiG, PGE, followed by a panel discussion (full details to be circulated shortly).

Tuesday 23 May (11:00 a.m. – 3:00 p.m., A-0 building of AGH University) – PCRec project meeting, dealing with the exchange of information on new technologies for recovering raw materials from waste, mainly WEEE.

Wednesday 24 May (9:00 a.m. – 5:00 p.m., Room 213, A-0 building of AGH University) – 3rd edition of the Conference „Young Researchers’ Innovative Ideas: Science-Start-up-Industry” consisting of PhD students and young researchers presenting to the industry various innovative solutions of their authorship (social, organizational, product marketing, and process-related).

Wednesday 24 May and Thursday 25 May (full day) – visits to KGHM’s kupferschiefer copper-silver and to the Wieliczka salt mines (a UNESCO world heritage site), organized by the Baltic Student Chapter of the Society for Geology Applied to Mineral deposits (SGA), who will also be holding their Annual Meeting.

Contact: Dr. Mike Mlynarczyk: michal.mlynarczyk@eitrawmaterials.eu ; Mob (+48) 697 713 617