Silica-Glass from the Libyan Desert

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A WIND-WORN lump of clear and transparent, pale yellowish-green silica-glass resembling bottle-glass from the Libyan Desert, has been presented to the Department of Minerals of the British Museum (Natural History) by the Survey of Egypt. This material has been recently discovered by Mr. P. A. Clayton of the Desert Surveys at latitude 25° 20′ N., longitude 25° 30′ E. (about 480 miles south-west of Cairo). It was found in considerable amount and over a wide area (20 km. by 20 km.) as isolated pieces up to 10 lb. in weight in the hollows between the sand-dunes. It closely resembles the problematical glass long known from Bohemia and Moravia, which has been cut as a gem-stone under the names ‘bottle-stone’ and ‘water-chrysolite’. This is also known as moldavite and, with the australites (‘blackfellow's buttons’), it is classed with the tektites, the origin of which is still obscure. The new glass from the Libyan Desert is found in much larger pieces and in greater quantity than any tektite yet known. It differs from the abundant silica-glass found last year by Mr. Philby around the meteorite craters at Wabar in Arabia in showing an indication of flow structure and in the almost complete absence of bubbles; but it forms a very suggestive link between tektites and the silica-glass that has been definitely proved to have been formed by the fall of large meteorites.