The Mines and Minerals of Lavrion - AltaiteLast Updated: 27th Jan 2020
By Branko Rieck
ALTAITE, PbTe, isometric
The mineral altaite has so far been found in Lavrion only in polished sections of skarn specimens from the contact aureole of the Plaka granodiorite intrusion. Fresh polished surfaces show silvery metallic grains with yellow tint that quickly tarnish to a blueish hue. Altaite was initially discovered by Dr. Uwe Kolitsch (2015) as the first fully confirmed discovery of a Te-bearing mineral could be made. Leleu (1973) describes – without adding details – tetradymite (Bi2Te2S) from a skarn in Plaka, but after his description no further finds of this paragenesis were made. As the original samples have gone missing, a modern verification is no longer possible.
The altaite-bearing samples originate from a very tough calcsilicate-skarn that is mineralized with pyrrhotite, little chalcopyrite and galena. The main constituents of the matrix are epidote, grossular-rich garnet, with minor clinozoisite, quartz, titanite and calcite. As an accessory mineral zircon is found within garnet as very pure and nearly euhedral crystals up to 50 µm. Altaite forms very small (max. 25 µm, usually 1-2 µm) anhedral grains, mostly as inclusions in pyrrhotite.
Altaite has been identified from samples from the Adami 2 Mine in the Plaka area. Two sampling spots along a stretch of about 25 meters in the upper workings of the adit are proven to contain altaite.
Fig. 1: SEM micrograph (BSE mode) that shows an unusually large altaite grain (white) in a matrix of massive pyrrhotite. Polished section of a pyrrhotite-bearing skarn specimen.
Fig. 2: SEM micrograph (BSE mode) that shows two tiny altaite grains (white) in a matrix of massive pyrrhotite. Polished section of a pyrrhotite-bearing skarn specimen.
Kolitsch, U., Rieck, B. and Voudouris, P. (2015): Mineralogy and genesis of the Lavrion ore deposit: new insights from the study of ore and accessory minerals. MinPet 2015, Leoben, Austria, September 10-13; abstract in Mitt. Österr. Mineral. Ges. 161, 66
Leleu, M., Morikis, A., and Picot, P. (1973) Sur des minéralisations de type skarn au Laurium (Grèce). Mineralium Deposita, 8, 259-263 (in French).
Rieck, B., Kolitsch, U., Voudouris, P., Giester, G. and Tzeferis, P. (2018): Weitere Neufunde aus Lavrion, Griechenland. Mineralien-Welt 29 (5), 32-77 (in German).
Thanks go to Dr. Uwe Kolitsch for constructive comments and diligent proofreading to improve this article.
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