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

Select a specimen: If more than one specimen is shown, you can select a particular specimen by telling us what is in the photo with it, a black and silver pen, a black mechanical pencil or one of those plus some number of coins, or you can let us make the selection.

Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. A link in that invoice will bring you back to checkout, no hassle.

Shipping: By Priority Mail or USPS Ground Advantage, whichever is cheaper, unless we find a better rate. Click > here < for shipping rates. Use back button to return to this page.