schaller: plancheite and shattuckite 131 



well emphasized in sulfur, as are certain quantitative relations, 

 but the number of sulfur crystals reported is too small to 

 make quantitative relations of much value. 



MINERALOGY. — Plancheite and shattuckite, copper silicates, 

 are not the same mineral. Waldemar T. Schaller, Geo- 

 logical Survey. 



The name plancheite was given by Lacroix,^ in 1908, to a blue 

 copper silicate from the French Congo, Africa. About five 

 years later a blue copper mineral from Bisbee, Arizona, sent to 

 the U. S. Geological Survey for identification, by Philip D. Wil- 

 son, of Bisbee, was determined by qualitative tests as probably 

 plancheite. Abundant material was available for various de- 

 terminations and it was soon found that several discrepancies 

 existed "between the properties of the two minerals from Arizona 

 and from Africa. Accordingly a detailed investigation of the 

 Arizona material was undertaken and it was determined that the 

 Arizona mineral was not plancheite and that an additional 

 new copper mineral was intimately associated with and geneti- 

 cally derived from the more abundant blue mineral, which in a 

 preliminary note- was named shattuckite, the other new copper 

 mineral being called bisbeeite. So far as known to the writer, 

 plancheite has not been found in Arizona. The essential proper- 

 ties of shattuckite and of bisbeeite were published in the Third 

 Appendix to Dana's System of Mineralogy. The paper describ- 

 ing in detail the properties of these two new copper silicates has 

 not yet been published. 



Zambonini^ has recently questioned the validity of shattuckite 

 as a separate species and has urged its identity with plancheite. 

 He gives a new analysis of plancheite which does not agree with 



1 Lacroix, a. Sur une yiouvelle espece mineral, provenant du Congo frangais. 

 Compt. Rend. 146: 722-725. 1908; Les mineraux accompagnant la dioptase de 

 Mindotdi {Congo frangais): plancheite, nov. sp. Soc. Fran?. Mineral. Bnll. 31: 247- 

 259. 1908. 



2 ScHAHER, W. T. Four new minerals. Journ. Wash. Acad. Sci. 5: 7. 1915. 

 ^ Zambonini, F. Sur I'identite de hi shattuckite et de la plancheite. Compt. 



Rend. 166: 495-497. 1918. 



