TANTALUM AKD NIOBIUM IN W. AUSTRALIA. 315 



exact species must remain in doubt. The typical manoano-tantaliteof 

 Wodgina differs from it in several respects, viz. : — 



(1) It contains far less tin oxide (O'o",, as against 8'9). 



("2) It is not quite so hard (6'5 as against 7'0). 



(3) It is quite opaque even in very fine powder. 



(4) Its colour is black and streak brownish black. 



(5) Its lustre is very dift'erent. 



It resembles on the other hand this mineral somewhat closely in 



(1) .Specific gravity (7'4: and 7"1). 



(2) Ratio of basic protoxides to acidic pentoxides being one to 



one. 



(3) Chief base being manganese, chief acid tantalic. 



(4) Absence of rare earths from both. 



G-RBENBUSiiES. — Up to the time of the writing of my j^revious 

 paper no traces of crystalline form had been obseiwed on any of the 

 Greenbushes tantalite. I have since seen a water-worn fragment of 25 

 grammes in weight which exhibits a radiated stiiicture similar to that 

 seen in some of the Moolyella ore. 



A number of stream tin ores from Greenbushes have been ex- 

 amined for tantalite and stibio-tantalite with negative results. It 

 would appear as if these minerals were coi?fined to a small portion only 

 ■of the field. Tantalum has, however, been detected in clean cassiterite 

 from this field. A clean crystal from a lode on the South Cornwall 

 Mine was found to yield the results given below, whilst a rolled pebble 

 from North Greenbuslies yielded 1'15% Ta205. 



Cassiterite, Greenhushcs. 



Tin dioxide 97'63 per cent. 



Tantalum pentoxide ... ... r76 „ 



Iron oxide, &c. ... ... ... 61 



10000 



Bellinger. — This is a new locality for tantalates, situated close 

 to the South Coast. The rock formation is granite traversed by veins 

 of pegmatite, one of which, twelve miles Avest of Point Malcolm, gave 

 promise of yielding muscovite of commercial quality. A mineral lease, 

 11 211, was taken up on this vein during 1907 in order to open up the 

 mica, and in the course of operations small ijuantities of a black 

 nraneral were met with, which was thought to be tin ore. Examination 

 proved it to be tantalate and niobate of iron and manganese varying 

 from ferro-tantalite to mangano-columbite in cojiiposition. The specific 

 gravities recorded were 5'59, 6"60, 7' 10, 7'60, indicating percentages 

 of tantalic oxide from 15 up to 75. Most of the mineral was in 

 irregTilar, broken fragments, but a few imjierfect tabular crystals were 

 noticed in which the faces ''a" and " 1) " were prominently developed, 

 whilst traces of '" u " were also seen. 



