Home > Mexico IV Ojuela II – January 19 > MS1751 Goethite after Parasymplesite

Goethite after Parasymplesite - Sold


Goethite is an iron oxide hydroxide, named after German poet and philosopher Johann Wolfgang von Goethe (1749-1832). Johann Georg Lenz (1748-1832) first proposed the mineral name in his 1806 Tabellen über das gesammte Mineralreich. Parasymplesite is a ferrous iron arsenate, named after its polymorphic relationship with the long known species symplesite (Ito et al., 1954).

A spray of bladed crystals to 2.4 cm protrudes from a limonite, matrix. Since both the pseudomorphs and the matrix consist largely of goethite, there is little contrast. Nevertheless an interesting pseudomorph. While similar samples may be labeled "after köttigite", an iron rich precursor (parasymplesite) is more likely. Imagine this specimen as a fine parasymplesite specimen, which oxidized after ground water levels dropped and stopped longer protecting these crystals.