Goethite | Common Iron Mineral
About the Mineral Goethite
Goethite pronounced "ger-tite" is a common iron mineral which takes on various forms and colours. It can be found all over the world and is present in abundance on Mars along with the mineral hematite. It often forms through the weathering of other iron-rich minerals and although usually black, can occur in shades of yellow, brown or red depending on the impurities present. Fine crystallised specimens of goethite are rare but can be found in Cornwall (United Kingdom), France and Russia.
Goethite can be translucent to opaque, it grades 5 to 5½ on Mohs scale of mineral hardness and was named in 1806 after the German poet Johann Wolfgang von Goethe who was a keen mineralogist. It's commonly found in rust and iron ore deposits and has been known since ancient times because it's the source of the yellowish brown colour in the pigment known as ochre.
The goethite mineral at the top of this article is on display in the Harvard Museum of Natural History, Cambridge, Massachusetts. Clicking the image redirects to the original photograph. Photo by Stone Mania ©
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