BY W. F. PETTERD, C.M.Z.S. 179 



The percentage composition of the mineral mixture is then 

 6"84 per cent. Fe Sg and 93"16 per cent, of a mineral con- 

 taining — 



100 00 



This last composition is that of the tennantite portion 

 of the above formula, and corresponds remarkably closely 

 with the percentage composition derived from the original 

 analysis, on the assumption that the only impurity in the 

 mineral is iron pyrites. In other words, the mineral is a 

 zinciferous tennantite, and the name of kupfer-blende 

 probably correctly applies to it. 

 "Analysis of a second sample: — 



The undetermined is probably H.,0, as the water was 

 not driven off at 100° C." (R. Sticht.) 



326. Tenorite. (^See Melaconite.) 



327. Tephroite fOrthosilicaPe of Manganese). 



Occurs in crystallised masses of a dark reddish-brown 

 colour and greasy lustre. Blythe River. 



328. Tetrahedrite ("Sulphide of Copper, Antimony, d^c.J. 

 This mineral is also known as grey copper ore, and as 



" fahl." The latter is the common appellation in Tas- 

 manian mining fields, but the term is rather ambiguous, as 

 it is indiscriminately applied to ores with the general char- 

 acteristics of this mineral. It is isometric in crystallisa- 



