'240 



REPORT OF NATIONAL MUSEUM, 1899. 



The natural colors of the ochcrs is dependent on the degree of h^^dra- 

 tion and oxidation of material and the kind and amount of impurities. 

 In a general way the hematites are of a deep-red color (Specimen No. 

 66075, U.S.N.M.), while the limonites are yellow or brown (Specimen 

 No. 61101, U.S.N.M.). Either color is liable to shade variations, 

 according to amount and kind of impurities. The colors are intensi- 

 fied or otherwise varied by roasting (Specimens Nos. 63056 and 63057, 

 U.S.N.M.). 



Artificial ochers are produced by roasting iron pyrites (sulphide. of 

 iron) or an artificial sulphate (green vitriol) (Specimen No. 61122, 

 U.S.N.M.). (See under Pyrite.) The materials known commercially 

 as rouge, crocus, and Indian red are quite pure ferric oxide, pre- 

 pared by roasting pyrite or by other artificial means. 



Composition of ochers in their natural condition. 



Natural color. 



Locality. 



Marksville, Page County, Virginia. 

 Rawlin.s, Wyoming 



Yellow ))rown... Hancock, Berks County, Pennsylvania 

 (Specimen No. 62787, U.S.N.M.). 



Deep brown Anne Arundel County, Maryland (Speci- 

 men No. 60843, U.S.N. M.). 



Deep red brown . Northampton County, Pennsylvania (Speci- 

 men No. 61103, U.S.N. M.) . 



Gray Northampton County, Pennsylvania (Speci- 

 men No. 61098, U.S.N. M.). 



Dark brown Brandon, Vermont (Specimen No. 66732, 



U.S.N.M.) Montgomery County, Alabama 



(Specimen No. 63339, U.S.N.M.). 

 Cartersville, Georgia (Specimen No. 63340, 

 U.S.N.M.). 



FesOa. 



39.0 

 90.2 



(136.67 



19.67 



b 42. 45 



C12.20 



d52.92 

 a 10. 57 



AI0O3. 



SiOo. 



33.0 

 finsol. 

 I 7.2 



H„0. 



11.5 



10.60 

 2.60 



11.85 



5. 23 



14. 62 

 7.40 



Alks. 



0.5 

 1.2 



a A part of the iron in a ferrous condition, 

 ciron exists mainly in a ferrous condition. 



h Contains also some manganese, 

 d Contains much manganese. 



a Made from red fo.ssiliferons ores mined at Atalla, Alabama, and Ooltewah, Tennessee. 

 6 Made by Iron Clad Paint Company, of Cleveland, Ohio, from ore mined in Wayne County, New 

 York, 

 c From ore mined at Lake Superior, Michigan, 

 d Ore from Jackson ml.ie, Micliigan. 



