

and Shepard's Treatise on Mineralogy. 339 



"There is a slight deficiency in the quantity of soda, but this salt 

 evidently consists of one atom sulphate of soda, one atom sulphate of 

 lime. 1ms is the composition of the variety from Villa Kubia, in 



Spain, originally analyzed by Brongniart. Formula : NSI-j-CalSl, or 



• * i 



NaS+CaS 



« It occurs m extremely brilliant, colorless and transparent crystals 

 imbedded in hydrated borate of lime, or Hayesine. They are in the 

 form of elongated oblique rhombic prisms, simply replaced on their 

 obtuse terminal edges, by single planes." 



but 



sum- 



ine Lederente of Dr. Jackson, which Mr. Alger retains as a 

 distinct species, is described as follows, on pages 214, 215. 



Ledererite. 



C. T. Jackson. {Am. Jour, of &i" Vol. xxv, 78.) 



" This mineral is composed, according to the analysis of A. A. 

 Hayes,* of silica, 49-47; alumina, 21-48; lime, 11-48; soda, 394- 

 phosphoric acid, 3-48 ; oxide of iron, 0-14 ; water, 8-58. 



"Sp.gr. 2-10. H.z=6. 



" It occurs in crystals which are sometimes colorless and transparent, 

 usually white and opake, or only translucent on the edges, some of 

 Jnem being of a pale salmon color. The crystals are in the form of 

 hexahedral prisms, deeply replaced on their terminal edges, or termi- 

 nated at both extremities by hexahedral pyramids, having at their 

 ttuts a small plane termination, perpendicular to the axis of the prism ; 

 indicating a regular hexahedral prism for the primary form. This 

 or m is further indicated by the separation of faces of cleavage made 

 risible by exposure to heat. Before the blowpipe, according to Haves, 

 11 becomes white, and divides at the natural joints ; at a higher tempo- 

 ^ture it fuses into a white enamel, which can be rendered more vitreous 

 °y continuing the blast ; a few bubbles are disengaged when it is thus 

 r eated. In the matrass, a slight empyreumatic odor is perceptible. 

 te ln ferior hardness and specific gravity, but more especially its py- 

 gnostic characters and chemical composition, clearly separate it from 

 e species hydrolite, or gmelinite, to which it has been referred : one 

 °nsisting of bisilicates of alumina and lime, silicate of soda, with six 

 p T cent, phosphate of lime, and only 8-58 water ; the other, by Mr. 

 nnell's analysis, of bisilicate of alumina, tersilicate of lime, soda and 

 P ash, n o phosphoric acid, and 21-66 per cent, water. 



some of the crystals are elongated, and measure one third of an 

 ctl »n the direction of the prismatic axis, but most of them possess 



• Am. Jour, of Sci., Vol. xxv, p. 84. 



