GUIDE TO THE MINERALOGIC COLLECTIONS 



123 



Colemanite is found quite abundantly in California, Nevada 

 and Oregon. Pandermite is mined near Pandemia in Turkey. 

 Colemanite is an important source of the borax of commerce. 



Borax (tinkal) Na,B 4 7 .10H 2 



Borax is a hydrous borate of sodium. 



It occurs in sharp, well formed monoclinic crystals trans- 

 parent to opaque resembling those of pyroxene in habit. The 

 color is white to gray sometimes inclining to greenish or bluish 

 and the luster is vitreous to dull. 



Borax is present in solution in many lakes of a saline or alka- 

 line nature and is found crystallized in the mud at the bottom 

 and in deposits in the surrounding marshes. Deposits of con- 

 siderable importance occur in Nevada and California. 



It is used in many industries such as -soap, glass making 

 etc., as a preservative and in washing, bleaching and antiseptic 

 preparations. 



Ulexite NaCaB,0 r ,.8H : .0 



Ulexite is a hydrated borate of sodium and calcium. 



It occurs in loose rounded masses of fibrous crystals, white in 

 color and with a silky luster. 



Its occurrence is similar to colemanite and borax and it is 

 found in Nova Scotia and Chile as well as in the borax localities 

 of Nevada and California. 



It is much used in the manufacture of borax. 



URANATES 

 Uraninite (pitchblende) 



Uraninite is a uranate of uranyl, lead, usually thorium (or 

 zirconium) and frequently metals of- the lanthanum and yttrium 

 groups. The relation between the bases, however, varies so 

 widely that no definite formula can be given. 



It rarely occurs in isometric crystals of octahedral habit but 

 is commonly found in botryoidal or granular masses pitchlike in 

 luster and appearance and generally black in color. 



Uraninite occurs as a primary constituent of granitic rocks 

 and as a secondary mineral with silver, lead and copper ores. 

 The main supply is obtained from Bohemia. It is mined, how- 



