278 ■ UNIVERSITY OF VIRGINIA PUBLICATIONS 



GENERAL REMARKS ON THE PROPERTIES, OCCURRENCE, AND USES OF ZIRCON. 



Elementary Zirconium. 



Properties and distribution. The element zirconium derives its name 

 from the mineral zircon, in which Klaproth* discovered the new earth 

 zirconia (Zr02) in 1789. It is somewhat closely allied to titanium, is quad- 

 rivalent, has an atomic weight of 90.6, and when crystallized has a density 

 of 4.25 and is hard enough to scratch rubies.f The crystallized form of 

 the element! somewhat resembles antimony in appearance, does not burn 

 in the air, and is soluble in hot concentrated acids. Amorphous zirconium 

 is a black powder which burns to the oxide when heated in air and is only 

 slightly attacked by acids. § 



Zirconium is rather widely diffused in small quantity in igneous rocks, 

 usually in the form of the silicate, zircon. It is also found in minute quan- 

 tity in certain sedimentary and metamorphic rocks. Professor Clarkeli 

 gives the average of zirconium in 298 analyses of igneous rocks made in 

 the laboratories of the United States Geological Survey as 0.025 per cent, 

 equivalent to 0.03 per cent of Zr02, and estimates the amount of Zr02 

 in the average composition of the lithosphere to be 0.03 per cent. In the 

 distribution of elementary substances in the earth's crust Vogt° estimates 

 the amount of zirconium with seven other elements (P, Mn, S, Ba, Fl, N, 

 and CI) to range from 0.1 to 0.01 per cent. 



Table of zirconium-bearing minerals. 



The following zirconium-bearing minerals have been recognized and 

 described. Excepting zircon and baddeleyite the minerals are rare and of 

 scientific interest only. Baddeleyite is known in quantity only in Sao 

 Paulo, Brazil. 



* Roscoe and Schorlemmer, Treatise on Chemistry, 1900, vol. ii, p. 656; Ohley, J., 

 Analysis, Detection and Commercial Value of the Rare Metals, 1907, p. 173; Browning, 

 P. E;, Introduction to the Rarer Elements, 1909, p. 75. 



t Roscoe and Schorlemmer, Op. cit., p. 657. 



I Remsen, I., Inorganic Chemistry, 1890, p. 413. 



§ Browning, P. E., Op. cit., p. 77. 



If Clarke, F. W., The Data of Geochemistry, Bull. 491, U. S. Geol. Survey, 2nd 

 edition, 1911, pp. 27, 32. 



° Vogt, J. H. L., Trans. Arner. Inst. Mug. Engrs., 1892, vol. xxxi, p. 128. 



