240 



The so-called Meerschaum prom the Richmond R/ITeb, 



N.S.W. 



I take this opportunity to mention also that there is a deposit 

 of very white and porous hydrous silicate of alumina on this 

 river, which has often been sent down to Sydney as meerschaum. 

 Probably tliis is partly due to its low specific gravity, for when 

 first immersed it floats upon water. It is sometunes said to 

 contain leaf impressions ; colour, dead white ; breaks with more 

 or less well-marked conchoidal fracture ; shows traces of 

 stratification ; very porous, and adheres strongly to the tongue ; 

 H = about 2 ; can be scratched by the thumb-nail, and leaves a 

 mark on cloth, but not readily. 



Sp. gr. after immersion in water for some time =: 1'16S. 

 Before the blowpipe blackens slightly at first, and becomes 

 harder after ignition ; it is infusible, and yields a blue mass when 

 ignited after moistening with cobalt nitrate ; this at once dis- 

 tinguishes it from meerschaum, which w"ould under those circum- 

 stances afford a pale pink-coloured mass. 



Analysis. 



Water, given off at 100° 



Combined water (loss on ignition) 



Insoluble silica... 



Soluble silica . . . 



Alumina 



Iron sesquioxide 



Lime 



Magnesia 



Alkalies ... 



Carbonic acid . , . 



3-28 



4-34 



51-35 



•11 



37-72 



•46 



•34 



1-25 



traces 



1-54 



100-39 



The low specific gravity is a most remarkable characteristic of 

 this mineral, but in other respects it answers to cimolite, the 

 KLjXdiXLa. of Theophrastus. 



[Plate.] 



