goethite - botryoidal goethite from Morocco - teaching hand specimen
Goethite - FeO(OH), variable as (Fe,Mn)O(OH)
Goethite is the most common simple iron oxide. It often contains some manganese.
Botryoidal comes from Greek, botrys, for cluster of grapes. The shape is caused by growth around a nucleus such as a sand grain. When many are growing nearby, they merge as in this specimen.
Goethite was named in 1806 by Johann Georg Lenz in honor of the German poet, novelist, playwright, philosopher, politician, and geoscientist Johann Wolfgang von Goethe. It is identified by a yellow brown streak. Similar appearing botryoidal hematite has a brick red streak and its botryoidal form typically has a duller surface than botryoidal goethite. X-ray diffraction was used to confirm the identification.
This was misidentified as hematite by the source. Locality data from Morocco is often unreliable and we are not sure of the locality we were given. These are good typical examples.
How do you pronounce this? American English: gaw thite British English: go thite German: roughly ger tite
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