Hinsdalite, a new mineral. 



255 



The Colorado mineral, or at least that sample of it which 

 was analyzed, represents a strontium hinsdalite just as the 

 only good analysis of svanhergite really represents a lead svan- 

 bergite. 



The water of the mineral is all water of constitution, that 

 is, it is driven off only at a high temperature. It was found 

 that practically no water was expelled up to 390°, the follow- 

 ing table showing the results obtained : 



Loss of ivater. 

 Temp. Total loss in weight 



110° 002 per cent 



170° 0-02 " 



250° 0-0S " 



390° .... 0-08 " 



590° 9'24 " 



The crucible was heated in an air oven for the temperatures 

 up to 250° ; above this heat, an electric furnace was used. 

 The results show that the water is lost between 400° and 600°, 

 approximately. 



In its relation to other members of the group, hinsdal- 

 ite is best considered as the lead type of svanbergite. It 

 may just as well be considered as an aluminous corkite, the 

 formula for corkite* being 2Pb0.3Fe 2 3 .2S0 3 .P 2 5 .6H 2 0. 

 The systematic place of hinsdalite is thus well fixed, and it adds 

 another well-defined mineral to a group which already includes 

 a considerable number of minerals (see paper in the number 

 following). The relations of these minerals, closest related to 

 hinsdalite, can be seen in the following tabulation : 



Svanbergite... 2SrO. 3A1 2 3 . 2S0 3 . P 2 6 . 6H 2 0. Rhomb., c=l-2063 



Hinsdalite 2PbO. 3A1 2 3 . 2S0 3 . P 2 5 . 6H 2 0. Ehomb., c=l-2677 



Corkite 2PbO. 3Fe 2 3 . 2S0 3 . P 2 5 . 6H 2 0. Ehomb., c=M842 



Beudantite... 2PbO. 3Fe 2 3 . 2S0 3 . As 2 5 . 6H 2 0. Ehomb., c = M842 



United States Geological Survey, 

 Washington, D. C. 



* Compare Lacroix, Mineralogie de la France, vol. iv, p. 592, 1911. 



