Quartz is a mineral which often form crystals of large dimensions
and 1 m sized crystals of quartz are not very rare indeed. But have you
ever heard of 20 m - and may be even more - quartz crystals ? They
exist, on a very remote farm in western Namibia, not too far from the
prominent Gamsberg tafelberg.
The Verloren farm has an interesting history on its own. The name
"Verloren" which means "lost" in dutch language, derives from the fact, that this farmland
was good, but virtually inacessible. Lost farmland hanging half way up
the Great Escarpment, 500 m above the neighbouring farm and 500 m below the namibian plateau.
So this piece of farmland was given for free to the
adjoining farmer with the condition to build an access road as soon as possible.
The farmer truly fulfilled his obligation and constructed a remarkably steep and narrow road.
To reach the "crystal mountain" you have to use this rocky road
and this is surely one of the most adventurous tracks you will ever
experience. We tried it first in 1988 and simply did not succeed. The
road was too steep for the petrol pump of our landrover and the engine
ran out of fuel every time half up the slope. Frustrating ! Finally we
gave up and returned to Windhoek. Since that time I ever dreamed of
returning to the crystal mountain...
In 1998 we tried it again, equipped with a new 4 x 4 Toyota, which
served us well during our three weeks of holiday in Namibia. We arrived at the
steep slope and this time we made it...but again this infamous track
took its toll. While driving upwards, the back doors of our vehicle
suddently failed and our complete luggage scattered around on the adjoining slopes
!
Finally we reached the rolling hills of the Verloren farm plateau and
after an hour hiking we gladly reached the crystal mountain. There it
was, a giant mass of almost pure white glassy quartz glistening in the
sun. And there were the crystals too : 10, 15, 20 meters... maybe even
more. No, they do not (or only rarely)form free standing
idiomorphic crystals, but you can easily identify the pyramidal crystal
shapes in the rock faces and from time to time - looking from the right
spots and the right angles - you can easily recognize large crystal
faces too.
And then there were this caves. Unique caves indeed ! I had heard
about them before : giant rhomboedral dolomite crystals up to 2 m form
carbonate inclusions in the quartz crystals, These dolomite crystals, which you
can find at many places, are subject to classic carstification, i.e. they
are leached away over the times by water and all what remains are empty voids
in the rhomboedral forms of the former crystals. Even this caves are
quite long and a namibian caver told me later that they reach a length
of more than 100 m. Pitty for us, that we didnt bring the right
equipment to go caving...
But imagine : A substantial cave developed by leaching of giant
dolomite crystals, which are mere inclusions in even larger quartz
crystals !
We left the place deeply satisfied to have the privilege to see
some of the largest crystals on earth. And if I ever get the chance
I will come back, this time with caving gear...
Update June 2005 : Maybe I get the chance this autumn. We are planning to go to Namibia in September to document this and other localties in the country. For more information please click here
Update October 2005 : We visited the locality in September, though only shortly. The good news is, that the place will be now opened up to tourists and that access will be much easier in the near future. Though we were not able to examine the cave in any detail, you can now find an excellent publication about the cave here.
Update December 2005 : You are now able to visit the locality by a virtual "walk through". Please have a try and enjoy here.
Update March 2006 : Google Earth Satellite image added, which clearly shows the Quartzberg structure from earth orbit here.
Update June 2006 : If you are still not convinced, that the Verloren quartz ridge is composed of real single crystals, please have a look to this newly added photo right !
Update February 2007 : More giant crystals ! The german Bode Verlag / Haltern recently published a major new book about Namibia (VON BEZING 2007), its minerals and mineral localities. This book includes a small chapter about the Verloren Quartz Berg and its minerals (pp. 352 - 353) and states, that apart from the well known giant quartz and dolomite crystals there are also giant calcite crystals up to 1 m, actinolite prisms up to 1 m length and radial tremolite "needles" up to 20 m (!!) length. The chapter also states, that there are even more megaquartz localities - though of overall smaller dimensions - scattered th roughout the Hakosberge, namely on the farms Gurumanas, Naos, Ibenstein, Dordabis and Friedental.
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The Natas / Verloren megaquartz in a nutshell :
Mineralogy : |
Quartz, dolomite, talc |
Crystal Size : |
Quartz crystals up to 20 m ( 50 m ?) and dolomite
crystals up to about 2 m |
Geology & Origin : |
Hydrothermal crystallisation of quartz / dolomite in fault zone in surrounding mica schist
with intense carstification of the dolomite.
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Current status : |
Plans are underway to open up the locality for tourists. |
Remarks : |
This site and smaller similiar sites in the vicinity urgently needs further research and
protection !
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Other notable & famous quartz occurences :
Note : Quartz is a very commong mineral, therefore well developed quartz crystals in sizes up to 1 m are not especially rare. However, there are some outstanding occurences, namely :
- Quartz caves of the Alps : Several tectonic fissures in gneissic rocks at various localities may reach cave size and are often filled with pure quartz crystals (rock crystals, Bergkristall) Sometimes these clear quartz crystals reach astonishing dimensions up to 1 m size and larger, namely from the Ankogel group / Austria, from the crystal caves Sandbalmhöhle and Pfaffenwald, Switzerland and also from the swiss Zingenstock.
- Giant clear quartz crystals up to 1 m and more occur in the northern parts of the Ural mountains, Russia and are mined for their beauty and optical properties at Doodo and Puiva.
- Large white vein quartz dykes are known from several parts of the globe and may reach many kilometers length. One of the most obvious - even from satellite images - is the bavarian Pfahl / southern Germany, which runs for almost 150 km and forms spectacular white rock exposures at Weißenstein / Regen and at Viechtach, both Bavaria.
- Large quartz veins with abundant clear rock crystals are common within Arkansas, USA and are often for sale on mineral fairs.
- Even larger quartz crystals - up to 4 m - are known from Brazil.
- The largest (??) quartz specimen on display, which was mined on the Otjua farm in Namibia - can be visited in the Kristallgalerie in Swakopmund, Namibia.
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Other notable & famous dolomite occurences :
- Large, splendid dolomite twins of optical quality up to 20 cm size are known from the Brumado magnesite deposit, Brazil
- Nice dolomite crystals up to 20 cm and more occur in cavities of massive magnesite at Eugui, Navarra, Spain
- Dolomite may form huge mountain ridges predominantly consisting out of dolomitized limestone such as the Dolomites in the southern Alps / Northern Italy.
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About 5 - 10 m large quartz prism in an quartz reef of Farm Verloren
Photo : A. Schmidt-Mumm, Adelaide
Center of the Quartzberg with dolomite - talc core
Photo : A. Schmidt-Mumm, Adelaide
Several meter large, well developed quartz crystals on Farm
Verloren
Source : BEHR, H.J., HORN, E.E., PORADA, H. : Fluid inclusions and genetic
aspects of the Damara orogen, pp. 611 -
654
12 m long weathered quartz crystal, showing excellent parting between growth sections
Photo : M. Bosshard, taken from Rykart "Quarz - Monographie", p.323
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Resources and relevant weblinks :
Scientific research on this probably unique occurence, which
definitely needs protection, was carried out by geologists of
Göttingen university in the course of the SFB 48
'Continental Earth Crust' in the 1980ties.
For further information please have a look at
MARTIN. H. & EDER, F.W. (1983) (eds.) Intracontinental
Foldbelts, Springer Verlag
and here :
BEHR, H.J., HORN, E.E., PORADA, H. : Fluid inclusions and genetic
aspects of the Damara orogen, pp. 611 -
654
and most recently :
BEZING, L. v. (2007) : Namibia - Mineralien und Fundstellen, Bode Verlag, Haltern 2007
For a detailed description of the cave system, please read MARAIS,E., MARTINI, J. & IRISH, J. (1995) : Gauab AS (Nambie Occidentale) : Une grotte dans de la dolomie megacristalline hydrothermale, in : Karstologia, No. 25, 2/1995, pp. 51 - 54 in our library section thanks E. Marais, who sended us his publication.
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