Sinai Desert Geode

April 24, 2010

20100424 – Saturday - Sinai Desert Geode 2

Photographer: John Powell
Summary AuthorJohn Powell

The photo above features a geode from the Sinai Desert on the Sinai Peninsula of Egypt. St Catherine's Monastery was built in the Sinai Desert by Justinian I around 530 A.D. to protect the hermits who had been gathering there for years. The monastery allegedly encloses Moses’ well and the original burning bush. Outside of the monastery complex, local stones such as druzy geodes and poor quality quartz crystals are sold by the local Bedouin. Geodes are typically ovoid shaped hollow concretions that form inside cavities of many kinds of rocks. In sedimentary rocks, for example, the cavities are created by the dissolution of previously existing concretions that grew within relatively soft sediments. They’re in-filled by intermittent episodes of water deposition having varying levels of mineral content. Agate crystals often result. When the deposition process does not completely fill the cavity, a hollow space remains, and the interior of the geode may then become encrusted with a fine layer of druzy crystals. Note that the cavity of this geode has similarities to the Star of David. Photo taken on March 11, 2010.