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Rochlitzer Berg is a mountain of volcanic origin in Saxony, southeastern Germany. It is situated south-west of the town of Rochlitz on the river Zwickauer Mulde. Its elevation is variously given as 348.9 m NHN, 348 m HN〔(【引用サイトリンク】title=TK 1207-43 (AV) )〕 or 353 m NN. The mountain is also known as ''Rochlitzer Collm''.〔from Sorabian ''chołm'' = „hill, mound“, see also Collmberg near Oschatz)〕 == Geology == The so-called ''Rochlitzer Porphyr'', a rhyolitic tuff, which makes up a large part of the mountain, was formed from deposits of late explosive eruptions of a volcano about 250 million years ago. The colour of the rock is usually reddish to reddish-violet, occasionally also reddish brown to beige. Its texture is grainy and marked by many pore-like cavities (macro-pores). While the designation as "porphyry" has been passed down through history and is commonly used, it is petrographically incorrect. The tuff rock has been used since roughly a thousand years all over the region, also by Renaissance master builders Arnold von Westfalen and Hieronymus Lotter. The latter used it for the Old Town Hall in Leipzig and Augustusburg castle. More recently, it was used for facing of Stadthalle Chemnitz and the Peasants' War Panorama near Bad Frankenhausen. Tuff was mined in up to 10 individual quarries. Since 1879 ''Vereinigte Porphyrbrüche auf dem Rochlitzer Berge'' ("United Porphyry Quarries on Rochlitzer Berg") have been responsible for the operations. Explosives have been used only since 1991 in the last operating quarry. The amount of rock to be quarried is limited for reasons of nature and landscape protection. The tuff rock of Rochlitzer Berg has been named in May 2006 as one of the 77 most important national geotopes on Germany by the Academy of Geosciences in Hannover. According to a ballot led by Heinz Sielmann Foundation in 2012, "Rochlitz Porphyry" is the fourth most beautiful natural wonder in Germany.〔(【引用サイトリンク】title=Heinz-Sielmann-Stiftung: Naturwunder 2012 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Rochlitzer Berg」の詳細全文を読む スポンサード リンク
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