THE PROPERTIES OF MINERALS. 659 



Stephanito— Freiberg, Saxony. (Cat. No. 49486, U.S.N. M.) 



Richtuondite — Ricbnioiul Hill, Collingwood, New Zealand. (Cat. No. 4X03'J, 

 U.S.N. M.) 



Polybasite— Delia S. mine, Aspen, Colorado. (Cat. No. 81037, U.S.N.M.) 

 Euargitc — Missouri mine. Park County, Colorado. (Cat. No. 51488, U.S.N.M.) 

 Stannite— Cornwall, England. (Cat. No. 13623, U.S.N.M.) 

 Kylindrito— Poopo, Bolivia. (Cat. No. 84059, U.S.N.M.) 

 Argyrodite — Freiberg, Saxony. (Cat. No. 52131, U.S.N.M.) 



Oxi/Kulphides. — The minerals here included are those sulphides in 

 which the sulphur is in ])art replaced by oxygen — that is, (•,omi)ounds 

 of sulphides and oxides. 



The type is illustrated by — 



Kermesite— South Ham, Quebec, Canada. (Cat. No. 16870, U.S.N.M.) 

 Oxides and oxyijen salts. — From the abundance of oxygen and its 

 nearly universal affinities, its combinations form by far the largest num- 

 ber of the compounds of the elements. The minerals of this class fall 

 into two general groups — the oxides of the elements and their combina- 

 tions. To the tirst group the general name oxides is given; to the 

 second, oxygen salts. The oxygen salts include a number of types of 

 minerals, such as carbonate, silicate, and phosphate. 

 The tyi)e oxide is represented by the following specimens: 



Cervantite — Fords Creek, near Gulzora, New South Wales. (Cat. No. 82476, 

 U.S.N.M.) 

 Zincite — Franklin, Sussex County, New .Jersey. (Cat. No. 50230, U.S.N.M.) 

 Hematite— Elba. (Cat. No. 16474, U.S.N.M.) 



Quartz — Buncombe County, North Carolina. (Cat. No. 45811, U.S.N.M.) 

 Rutile— Magnet Cove, Arkansas. (Cat. No. 50530, U.S.N.M. ) 

 Limonito— Saxony. (Cat. No. 2029, U.S.N.M.) 



Brucit( — Texas, Lancaster County, Pennsylvania. (Cat. No. 49613, U.S.N.M.) 

 Ilydrotalcitc— Snarum, Norway. (Cat. No. 49026, U.S.N.M.) 



Oxygen salts, borates, aluminates, chromites, ferrites, and manganites. — 

 Borontrioxide, BaOj, under the proper conditions, will combine with 

 other oxides to form borates. Alumina, ALO,, acts with oxides of 

 stronger bases as an acid-forming oxide, and unites with them to form 

 aluminates. Chromic oxide, Cr20:i, and ferric oxide, Fe203, unite with 

 oxides of stronger bases to form chromites and ferrites. Oxide of man- 

 ganese, Mn.O:), acts as an acid-forming oxide toward stronger bases, 

 and forms with them manganates. 



The following sj)ecimens are illustrative of these types: 



Ulexite— Columbus, Nevada. (Cat. No. 14379, U.S.N.M.) 



Su.ssexite — Franklin, Sussex (Jounty, New Jersey. (Cat. No. 47543, U.S.N.M.) 

 Colemauite — Near Calico, San Bernardino County, California. (Cat. No. 47571, 

 U.S.N.M.) 

 Chrysoberyl— Haddam, Connecticut. (Cat. No. 13370, U.S.N.M.) 

 Spinel— Southfield, Orange County, New York. (Cat. No. 46546, U.S.N.M.) 

 Chromite— Zanina, Turkey. (Cat. No. 18370, U.S.N.M.) 

 Magnetite— Orange County, New York. (Cat. No. 46546, U.S.N.M.) 

 Franklinite — Franklin, Sussex County, New Jersey. (Cat. No. 16529, U.S.N.IM.) 

 Braunite— Jakobsberg, Sweden. (Cat. No. 47444, U.S.N.M.) 

 Psilomelane — Romaneche, France. (Cat. No. 46375, U.S.N.M.) 



