Tektites and the Lost Planet 



By Ralph Stair 



National Bureau of Standards 



[With 4 plates] 



Tektites, or small glass objects from out of the sky, have long been 

 of great interest to scientists in many fields. Found in great quantities 

 (literally by the million) and in many places over the earth's surface, 

 they have often been overlooked or else casually collected and used 

 for such things as weapon points by the cave dw^ellers of paleolithic 

 times. In Australia during the early gold-rush days, and in Texas, 

 where they were popularly known as black diamonds (Barnes, 1940), 

 they were widely distributed for use as jewels and ornaments. 



These little glass objects, known as australites in Australia, riza- 

 iites in the Philippines, bediasites in Texas, moldavites in Bohemia, 

 billitonites in Borneo, and by other names, including Darwin and 

 Libyan Desert glass, usually vary in size from a fraction of an ounce 

 to almost a jDound in weight. In shape they range from irregular to 

 such symmetric forms as buttons, spheres, ovals, pears, dumbbells, 

 teardrops, winged bodies, rods, and disks. In color, although the re- 

 covered object uually varies from black to a dark shade of green, thin 

 polished sections range from nearly clear through various shades of 

 green to amber or brown. The specimens found in each locality, usu- 

 ally spread over an extended area, as the south half of Australia and 

 a number of adjacent islands in the case of the australites, have common 

 characteristics that indicate original association or common source. 

 Similarly, the chemical and physical resemblances among tektites 

 (Suess, F. E., 1914) found in other localities justify their being 

 grouped into similar subfamilies such as the moldavites of Bohemia. 



THE COMPOSITION AND ORIGIN OF TEKTITES 



Studies of the compositions and other characteristics of tliese glasses 

 have revealed many facts that form the basis for interesting deduc- 

 tions regarding their origin. They have a high silica content with 

 the major secondary constituents being the oxides of aluminum, iron, 

 magnesium, calcium, sodium, and potassium (see table 1) and re- 



217 



