TIN ORE. 



Eemirks on Tin Ore, and what may appear like it. 



[Read hefore the Eoyal Society of Neiu South Wales, 20th November, 1872, 

 by Adolph Leibitts, Esq., PA. I>., Senior Assayer of the Sydney Branch 

 of the Royal Hint.'] 



Aftee more than nine months have elapsed since the excitement 

 respecting our Tin discoA'eries, both here and in Queensland, 

 began, it may almost seem superfluous to say anything about tin 

 ore. Many, no doubt, have already found out to their cost, that 

 the old proverb, " it is not all gold that glitters" may be supple- 

 mented by saying, " it is not all tin that looks like it." 



It is very curious that at first few (if any) samples of tin ore 

 ■were to be seen which were not highly satisfactory. G-radually, 

 as the tin fever spread, samples were more frequent containing 

 but little tin, and lately titaniferous iron and tungstate of iron 

 were the rule rather than the exception. 



The colour of native tin ore varies from white to pink, ruby- 

 red, grey, greyish-black to black ; it therefore is certainly no 

 very reliable criterion for distinguishing tin ore. 



A safer characteristic is the weight, or specific gravity, that of 

 tin ore being 6'8 to 7'0. Unfortunately, however, the specific 

 gravity of tungstate of iron is nearly the same as that of oxide of 

 tin, in fact a little higher, being 7'19 to 7"55. 



Titaniferous iron has a specific gravity of from 4"5 to 5'0, and 

 magnetic iron 4'9 to 5'2. 



Basaltic hornblende and silicate of iron have also come under 

 my n£)tice as having been mistaken for tin ore ; but the specific 

 gravity of the former being only 3" 1 to 3 "4, and that of the latter 

 3"8 to 4"2, ought to have saved such mistakes. The colour of the 

 powdered ore forms a much better criterion than that of the un- 

 powdered ore. The powder of good tin ore varies only from 

 whitish grey to dark drab, while tungstate of iron powders red- 

 dish brown, and titaniferous iron black. 



Hitherto most of the samples which came under my notice 

 appear to have been mistaken for tin ore on account of their dark 

 granular pieces having been taken for such ; but I have here a 

 sample, which I examined lately, and which consists of blackish 



