The Mines and Minerals of Lavrion - Agardite-(Ce)Last Updated: 15th Feb 2019
By Branko Rieck
AGARDITE-(Ce), CeCu6(AsO4)3(OH)6 · 3H2O, hexagonal
Please also note the general remarks here!
Crystals of Agardite-(Ce) appear as thin hexagonal crystals, that are usually found in radial sprays, but occasionally also as randomly scattered on the matrix (Fig. 2, top left) or even filling vugs completely (Fig. 2, center). Their color ranges from white to “apple-green”. Blue-green shades are rarer but do exist. Again, color is not a distinguishing feature of agardite-(Ce)! It can easily be confused with the other minerals of the agardite subgroup, goudeyite and zálesíite. Plumboagardite due to its scarcity and mixite due to its characteristic paragenesis are both less prone to be mixed up with agardite-(Ce). Looking closer at the internals of the individual crystals it becomes clear, that the vast majority is chemically zoned along both the a-axis and the c-axis. However, one characteristic shared with agardite-(Y) is that there also exist crystals that lack this zoning and are composed of mostly “pure” agardite-(Ce) (with Ce > 90% of the REE). Fig. 3 shows one such example.
Agardite-(Ce) is quite often the only mineral in vugs in the gossan matrix. If not, Cu-bearing adamite is the most common mineral to accompany it, followed by conichalcite. Malachite and azurite are often seen in the vicinity, too. Quite a bit rarer are associations with other copper-bearing minerals like parnauite, brochantite, rosasite and cornwallite.
Apart from finds at the Kamariza Dump agardite-(Ce) occurs most prominently at the Hilarion and Christiana mines. The most productive places in the Hilarion area are concentrated at the 2nd and 3rd levels, while in the Christiana area the 1st, 2nd and 3rd levels yield great specimen.
Fig. 1: Agardite-(Ce).
Fig. 2: Agardite-(Ce).
Fig. 3: Agardite-(Ce).
Fig. 4: Agardite-(Ce).
Fig. 5: Agardite-(Ce).
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