The Mines and Minerals of Lavrion - AmarantiteLast Updated: 21st Mar 2020
By Branko Rieck
AMARANTITE, Fe3+2(SO4)2O · 7H2O, triclinic
In a so far rather unnoticed area at the 4th Level of the Hilarion area, a highly interesting paragenesis of sulfate minerals was discovered in fall 2013 (Rieck et al., 2018). There are quite a few similarities with the sulfate localities in Plaka and Sounion, however also marked differences may be observed. This leads to a slightly different mineralization and consequently new discoveries for Lavrion. On a single piece, picked up at the floor of the adit, amarantite forms radial aggregates in matrix. The color, an intense orange-brown, and the cleavage are distinct (see Figure 1). The individual, stout crystals tend to split into fine, individual fibers at the crystal terminations.
The matrix consists of gypsum, melanterite and kröhnkite. Amarantite fibers in some parts quite often grade into pseudomorphs of copiapite after amarantite, containing also fibroferrite, hohmannite and/or metahohmannite.
As of March 2020 amarantite is a single-locality mineral at the Lavrion Mining District. The spot where it has been found is a small side adit at the 4th level of the Hilarion Mine. At this place a number of sulfate-rich secondary minerals have been found.
Fig. 1: Orange-brown, radiating aggregates of amarantite in a matrix of melanterite (green), kröhnkite (blue) and gypsum (colorless, partly colored yellow from inclusions of hohmannite/metahohmannite). From the 4th level of the Hilarion area. FOV: 6 mm.
Thanks go to Dr. Uwe Kolitsch for constructive comments and diligent proofreading to improve this article.
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).
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