The Earth Story

This spectacular location is the Bastei Bridge over the Elbe River in eastern Germany near the city of Dresden. The rocks are sandstones of the Elbe formation, deposited in waters of a shallow sea during the Cretaceous period. At the time, sea level was much higher than today and oceans covered many of the continents. Rivers brought sand grains pouring into the area that is now central Europe; those sand grains were cemented into strong layers of sandstone. Once the rocks were exposed…they cracked, allowing water into vertical layers. Those spots eroded, but areas that didn’t crack stood strong against erosion, eventually creating this topography. The bridge over the Elbe river was constructed in the mid-1800s out of rocks of the Elbe Sandstone, and today sits within Saxon Switzerland National Park. -JBB Image credit: http://upload.wikimedia.org/wikipedia/commons/4/4a/Basteibrücke_morgens_%28Zuschnitt%29.jpg http://books.google.com/books?id=-TI55urJYyEC&pg=PA201&lpg=PA201&dq=Elbe+sandstone+Geology&source=bl&ots=7SO5J_znXh&sig=dbjtSvM0bwWYX6BM83tMO0o_35c&hl=en&sa=X&ei=zSsJU-LZGc_PkQemrIHgCA&ved=0CFUQ6AEwBQ#v=onepage&q=Elbe%20sandstone%20Geology&f=false

Bastei Bridge and the Elbe Sandstone Mountains This spectacular location is the Bastei Bridge over the Elbe River in eastern Germany near the city of Dresden. The rocks are sandstones of the Elbe formation, deposited in waters of a shallow sea during the Cretaceous period. At the time, sea level was much higher than today and oceans covered many of the continents. Rivers brought sand grains pouring into the area that is now central Europe; those sand grains were cemented into strong layers of sandstone. Once the rocks were exposed…they cracked, allowing water into vertical layers. Those spots eroded, but areas that didn’t crack stood strong against erosion, eventually creating this topography. The bridge over the Elbe river was constructed in the mid-1800s out of rocks of the Elbe Sandstone, and today sits within Saxon Switzerland National Park. -JBB Image credit: http://upload.wikimedia.org/wikipedia/commons/4/4a/Basteibr%C3%BCcke_morgens_%28Zuschnitt%29.jpg http://books.google.com/books?id=-TI55urJYyEC&pg=PA201&lpg=PA201&dq=Elbe+sandstone+Geology&source=bl&ots=7SO5J_znXh&sig=dbjtSvM0bwWYX6BM83tMO0o_35c&hl=en&sa=X&ei=zSsJU-LZGc_PkQemrIHgCA&ved=0CFUQ6AEwBQ#v=onepage&q=Elbe%20sandstone%20Geology&f=false

The Dresden Green. Green diamonds get their colour from radiation, whether natural (from an elevated concentration of say Uranium and Thorium in the local rocks) or man made, induced in a lab. It is impossible to distinguish gemmologically which type of radiation induced the colour, so the only green diamonds to get natural colour on their grading certificates are those with a secure chain of custody from mine to grading laboratory, or that have impeccable historical qualifications dating them to before we learned how to play with the atom. The 40 carat Dresden Green is one of the latter diamonds, and the largest natural green in existence. Greens with an intense colour over a carat are almost unheard of. Mined in India, probably at Kollur in Golconda district of Andhra Pradesh, it passed from hand to hand through obscure trading networks all the way to Europe, where there is firm documentary evidence of its existence with its current hue in 1722. It was examined by the Gemological Institute of America in 1987 hoping to acquire evidence that might allow separation of natural stones, without success. It has been kept in the green vault at Dresden palace since 1742, having been bought in London in 1726 by Friedrich Augustus II, Elector of Saxony. The court jeweller set it into a badge of the Order of the Golden Fleece, a very popular order of chivalry in the Holy Roman Empire. The Hope diamond occupied a similar place in the French king's guarde robe. It was reset into a hat badge in 1786. The great green survived the fire bombing of the city in the second world war, was removed by the Russians in 1945 and returned to the then East Germany in 1958. As in so many of these posts, one priceless gem incorporates a tremendous amount of geology and history, lying at the interface between two areas of human endeavour, and informing both. Loz Image credit: Famous diamonds http://famousdiamonds.tripod.com/dresdengreendiamond.html includes a link to a free article from Gems & Gemology: http://www.gia.edu/Winter-1990-A1-Dresden-Diamond-Kane http://www.jckonline.com/article/280839-Provenance_of_a_Green_Diamond.php http://artemisiasroyalden.wordpress.com/2013/02/20/famous-stones-the-dresden-green-diamond/