Two phonolite quarries, the Railway Quarry and the Ariskop Quarry, are located 25 km S of Windhoek, on the road to Rehoboth. The two open pits are less than 1 km apart. The Railway Quarry (west side of the road) has been inactive [in 2011] for the last 10-15 years, whereas the Ariskop Quarry (east side of the road) has been active during at least the last decade and was active in 2011. Most of the minerals, including the type minerals, collected in recent years came from the workings of the Ariskop Quarry.
Note that each of the two quarries extracts material from a different intrusion, differentiated by its geochemical features (F. Koller, pers. comm. to U. Kolitsch, 2015).
Mineralogy is somewhat similar to that of the Saint-Amable sill (Demix-Varennes quarry), Québec, Canada, the Point of Rocks phonolite in New Mexico, USA and, in part, to that of Mont Saint-Hilaire. The most notable difference between these localities is the extreme scarcity of eudialyte-group minerals at Aris.
IMPORTANT NOTES on the mineral list (updated/cleaned up in May, June and July 2006, September & December 2007, August 2008, August 2009, May 2011, October 2011 and April 2016 by Uwe Kolitsch; see also booklet of Kolitsch et al., 2016):
1) Several other species were reportedly found and/or sold by dealers, but have never been confirmed. They are, in alphabetical order:
- gyrolite (confused with globular fluorite? there is also an apparently new mineral with an appearance similar to that of gyrolite);
- hiorthdalite II (confused with nenadkevichite or some other labuntsovite-group mineral?);
- iraqite-(La) (confused with sazhinite, probably because the powder diffraction patterns are similar);
- tetranatrolite (a sample labeled as "tetranatrolite" turned out to be makatite);
- zakharovite (in fact, the mineral is the unnamed Fe-analogue of zakharovite).
2) Eudialyte, originally mentioned in von Knorring & Franke (1987) and von Knorring et al. (1992) has been confirmed - as a eudialyte-group mineral - for the first time only in 2008 (a single specimen) and then again in 2009 (another single specimen) and 2016 (several specimens). EDS analyses of several specimens suggest eudialyte sensu stricto (Kolitsch et al., 2016); no EPMA of these eudialyte-group specimens are available yet. Most "eudialytes" in collections are probably villiaumite.
A larger number of presently unidentified minerals, some of them certainly new to science, are under study in various laboratories, partly in collaborative efforts (Vienna, Tempe, Copenhagen, Oslo, Ottawa, Moscow).
103 valid minerals. 5
- type locality of valid minerals. 4 erroneous literature entries.
Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!
This geological map and associated information on rock units at or nearby to the coordinates given for this locality
is based on relatively small scale geological maps provided by various national Geological Surveys.
This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
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Burger, A.J. and Walraven, F. (1977) Summary of age determinations carried out during the period April 1975 to March 1976. Annals of the Geological Survey of South Africa, vol. 11, 323-329.
Von Knorring, O. and Franke, W. (1987) A preliminary note on the mineralogy and geochemistry of the Aris phonolite, SWA/Namibia. Communications of the Geological Survey of South West Africa / Namibia, 3, 65.
Von Knorring, O., Petersen, O. V., Karup-Moller, S., Leonardsen, E.S., and Condliffe, E. (1992) Tuperssuatsiaite from Aris phonolite. Neues Jahrbuch für Mineralogie, Monatshefte, 1992, 145-152.
Niku-Paavola, V. (1997) Alkaline rocks in the Aris area, Central Namibia. Ph. D. Thesis Department of Geology and Mineralogy, University of Helsinki, 71 pp.
Petersen, O.V., Fockenberg, P.C., Toft, P.C., and Rattay, M. (1997) Natrophosphate from Aris phonolite. Neues Jahrbuch für Mineralogie, Monatshefte, 1997, 511-517.
Garvie, L.A.J., Devouard, B., Groy, T.L., Càmara, F., and Buseck, P.R. (1999) Crystal structure of kanemite, NaHSi2O5·3H2O, from the Aris phonolite, Namibia. American Mineralogist, 87, 1170-1175.
Wartha, R., Palfi, A., Niedermayr, G., Brandstätter, F., and Petersen, O.V. (2001) Der Aris-Phonolith-Komplex und seine Mineralien. In Bahmann, U. and A. (Eds.), Namibia – Zauberwelt edler Steine und Kristalle, Bode-Verlag, Haltern, Germany, pp. 172-179 (in German).
Niedermayr, G., Gault, R.A., Petersen, O.V., and Brandstätter, F. (2002) Korobitsynite from the Aris phonolites, Windhoek, Namibia. Neues Jahrbuch für Mineralogie, Monatshefte, 2002, 42-48.
Petersen, O.V., Niedermayr, G., Pekov, I.V., Balić Žunić, T., and Brandstätter, F. (2004) Tsepinit-Na und Labuntsovit-Mn, seltene Mineralien aus dem Phonolith von Aris, Namibia. Mineralien-Welt, 15(2), 44-48 (in German).
Sturla, M., Yakovenchuk, V.N. and Bonacina, E. (2005) Aris, Namibia: geo-paragenesi et minerali. Micro, no. 1, 55-80.
Wartha, R., Palfi, A., Niedermayr, G., Brandstätter, F., and Petersen, O.V. (2006) Der Aris-Phonolith-Komplex und seine Mineralien. In: Jahn, S., Medenbach, O., Niedermayr, G. & Schneider, G., Eds. (2006) Namibia – Zauberwelt edler Steine und Kristalle. 2nd ed., Bode-Verlag, Haltern, Germany, pp. 228-239 (in German).
Cámara, F., Ottolini, L., Devouard, B., Garvie, L.A.J., and Hawthorne, F.C. (2006) Sazhinite-(La), Na3LaSi6O15(H2O)2, a new mineral from the Aris phonolite, Namibia: Description and crystal structure. Mineralogical Magazine 70, 405-418.
Ellingsen, H.V. (2006) Sérandit aus Aris, Namibia. Mineralien-Welt 17(3), 51 (in German).
Piilonen, P.C., Rowe, R., Grice, J.D., Gault, R.A., Cooper, M., Kolitsch, U., and Lechner, W. (2005) Two new sodium rare-earth fluorcarbonates from the Aris phonolite, Namibia. Oral presentation, 32nd Rochester Mineralogical Symposium, Rochester, NY, USA, April 14-17, 2005, abstract in Program and Abstracts, 27-28 and in Rocks & Minerals 82 (2007) 243-244.
Piilonen, P.C., McDonald, A.M., Grice, J.D., Rowe, R., Gault, R.A., Poirier, G., Cooper, M.A., Kolitsch, U., Roberts, A.C., Lechner, W., and Palfi, A. (2010) Arisite-(Ce), a new rare-earth fluorcarbonate from the Aris phonolite, Namibia, Mont Saint-Hilaire and the Saint-Amable sill, Quebec, Canada. Canadian Mineralogist 48, 661-671.
Piilonen, P.C., McDonald, A.M., Grice, J.D., Cooper, M.A., Kolitsch, U., Rowe, R., Gault, R.A., and Poirier, G. (2010) Arisite-(La), a new REE-fluorocarbonate mineral from the Aris phonolite (Namibia) with descriptions of the crystal structures of arisite-(La) and arisite-(Ce). Mineralogical Magazine, 74, 257-268.
Marsh, J.S. (2010) The geochemistry and evolution of Palaeogene phonolites, central Namibia. Lithos 117, 149-160.
Yakovenchuk, V.N., Ivanyuk, G.Yu., Pakhomovsky, Y.A., Selivanova, E.A., Mikhailova, J.A., Krivovichev, S.V., Zolotarev, A.A. and Zalkind, O.A. (2011) Ellingsenite, Na5Ca6Si18O38(OH)13·6H2O, a new martinite-related mineral from phonolite of the Aris alkaline complex (Namibia). Canadian Mineralogist, 49, 1165-1173.
Horváth, L. and Horváth, E. (2011) Hilairite from the Ariskop quarry, Aris, Namibia. Aris Group Bulletin #16 (2011 11 28).
Horváth, L. and Horváth, E. (2011) Pectolite from the Ariskop quarry. Aris Group Bulletin #17 (2011).
Chukanov, N.V., Britvin, S.N., Blass, G., Belakovskiy, D.I., and Van, K.V. (2012) Windhoekite, Ca2Fe3+3-x(Si8O20)(OH)4·10H2O, a new palygorskite-group mineral from the Aris phonolite, Namibia. European Journal of Mineralogy, 24, 171-179.
Jost, B.M. (2012) Origin of water in miarolitic cavities of the Ariskop phonolite, Namibia. Master’s Thesis, ETH Zürich, Switzerland, 64 pp.
Rastsvetaeva, R.K., Aksenov, S.M., and Verin, I.A. (2012) Crystal structure of the NaCa(Fe2+,Al,Mn)5[Si8O19(OH)](OH)7·5H2O mineral: A new representative of the palygorskite group. Crystallography Reports, 57, 43-48.
Koller, F., Škoda, R., Palfi, A.G., and Popp, F. (2013) Phonolites of the Aris and Rehoboth areas, central Namibia, Africa. Mineralogical and Petrological Conference MinPet 2013, Bratislava, Czech Republic, May 23-24, abstracts volume, p. 40.
Rastsvetaeva, R.K., Aksenov, S.M., Chukanov, N.V., and Tremmel, G. (2013) Crystal structure of a new mineral of the labuntsovite group: Ca, Na-ordered analogue of korobitsynite. Doklady Physical Chemistry, 452, Part 2, 239-242.
Blass, G. and Tremmel, G. (2014) Neptunit und weitere neue Mineralien aus den Phonolith-Steinbrüchen von Aris, Windhoek. Mineralien-Welt 25(1), 76-83 (in German).
Jahn, S., von Bezing, L., and Wartha, R. (2014) Aris bei Windhoek in Namibia. Mineralien-Welt 25(1), 84-110 (in German).
von Bezing, L., Bode, R., and Jahn, S. (2014) Namibia. Minerals and localities. Edition Schloss Freudenstein, Bode Verlag, Salzhemmendorf, 608 pp. (in German). [section on Aris: pp. 12-35].
Jost, B.M., Koller, F., Vogel, N., Ulmer, P., and Driesner, T. (2014) Origin of water in miarolitic cavities of the Ariskop phonolite, Namibia. Goldschmidt 2014, 8-13 June, Sacramento, California USA, Abstracts, 1177.
Jahn, S., von Bezing, L., Wartha, R., Blass, G., Tremmel, G., Sturla, M., Cerea, P., and Ciriotti, M.E. (2015) Aris, Namibia. Località alcalina mondiale. Micro, 3/2015, 102-147.
Haugen, A. (2015) Mineraler fra Aris-steinbruddene i Namibia. Norsk mineralsymposium 2015, 71-78 (in Norwegian).
Blaß, G., Kolitsch, U., Tremmel, G., and Esche, J. (2016) Neue Mineralienfunde aus den Phonolithbrüchen von Aris in Namibia. Mineralien-Welt 27(4), 48-60 (in German).
Kolitsch, U., Blaß, G., Jahn, S., Cámara, F., von Bezing, L., Wartha, R. R., Tremmel, G., Sturla, M., Cerea, P., Skebo, M., and Ciriotti, M. E. (2016) Aris - mineralogy of the famous alkaline phonolite. AMI - Associazione Micromineralogica Italiana, Cremona, Italy, 95 pp.