1814.] Mineral called Hauyiie. 199 



As hauyne is not completely decomposed by muriatic acid, the 

 silica still retaining a portion of* alumina, and even of lime, after 

 baring been repeatedly boiled in that acid, it does not appear that a 

 very accurate analysis can be expected when conducted by means ot 

 that acid. It would have been better to have fused the hauyne with 

 potash, and with nitrate of barytes, in order to obtain its several 

 constituents in a state of purity. But as 1 had not a proper 

 quantity of hauyne in a state of sufficient purity, I was under the 

 necessity of deferring that mode of analysis to another time. 



The traces of copper suspected by Vauquelin I could not detect 

 by means of sulphureted hydrogen gas. 



The great quantity of sulphuric acid in this mineral, while its 

 hardness is such as to scratch glass, is surprising. This circum- 

 stance distinguishes hauyne from all other minerals. Probably this 

 acid in the mineral is not merely in combination with the lime, but 

 with all the constituents, and particularly with the potash, from 

 which it is separated by the action of the muriatic acid. 



The emission of sulphureted hydrogen gas when hauyne is 

 treated with muriatic acid is no less remarkable. No traces of 

 pyrites, or any similar mixture, can be perceived in it. Hence this 

 gas would seem to be chemically united with the other constituents- 

 of the mineral. 



The presence of sulphur in it seems to be connected with the 

 geognostic relations of hauyne ; for as it is always found in the 

 neighbourhood of beds producing volcanic fire, and therefore 

 abounding with sulphur, we may conclude that it is of contempora- 

 neous formation with these beds. 



I consider hauyne as nearly related to the family of zeolites.* 

 It agrees with them in its specific gravity, hardness, and other 

 external characters ; it gelatinizes in acids, melts before the blow- 

 pipe with effervescence, and contains a quantity of potash and the 

 same kind of earths that the zeolites contain. It differs from them 

 in the great quantity of sulphuric acid which it contains. On this 

 account it would seem to be related to the lapis lazuli ; though it is 

 probable that the sulphate of lime found in that mineral by Klap- 

 roth was owing to the presence of some foreign body with which it 

 was contaminated, as no such substance was found by Clement and 

 Desormea in ultramarine; but both lapis lazuli and hauyne, if we 

 ept the colour, agree in several properties which belong to the 

 zeolites. 



• 1 «prak «r the family of zeolite* as eitabl'ulieil by Hauifman in his Ihndbach 

 4ec Alincralogir, b. it. \>. 517. 



