Diogenite
Found October 2000
18° 43.525' N., 54° 43.829' E.
A single lightly weathered (W1) stone, weighing 156 g, was found in the desert of Oman by a German team. It was classified by Dr. J. Otto at the Institut für Mineralogie, Universität Freiburg, as one of the most highly shocked diogenite yet discovered, with a shock stage of S4. This breccia exhibits a fragmental texture, which has been interpreted to be a characteristic of impact ejecta. For more details on the formation of diogenites visit the Johnstown page.
The photo above shows a 0.88 g half slice of Dhofar 778, which exhibits profound shock-veining. Increased magnification reveals that fragmentation is present to a very fine scale. It is thought that the melt veins were formed and quenched within a few microseconds. The top photo below is a high resolution image of this diogenite, courtesy of Stephan Kambach. This is a highly polished section revealing a greenish color similar to that of Tatahouine. The bottom photo below shows the fusion-crusted side of the main mass.
Click on photo for a magnified view
Photo courtesy of Stephan Kambach
