274 Dr. Heddle on the Galadite of Hnidinger. 



A radiated mineral of a still more decided pink tinge, which 

 is found at Glenarbuck and the Long Craig in Dumbartonshire, 

 is also called Galactite. The fibres of all the specimens that I 

 have seen run so much into the Kilpatrick or zeolitic quartz, 

 that I have not been able to free any specimen sufficiently from 

 this matrix to rely upon the correctness of a quantitative ana- 

 lysis ; by a qualitative examination, however, I have ascertained 

 that this is the same substance as the above ; lime here also 

 being present in small quantity. 



These are, I believe, all the localities of Galactite, and all are 

 in composition merely Natrolite (the calculated per-centages of 

 which, for the sake of comparison, arc appended in a foot-note*) j 

 a small, generally a trifling, proportion of lime in each replaces a 

 portion of the soda, the full amount of which in Natrolite is 16"2 

 per cent. ; this small portion of lime it is which gives to these 

 Natrolites their whiteness and opacity, and doubtless prevents 

 their assuming the definite crystalline form which the pure 

 mineral under favourable circumstances adopts. 



Natrolite, though not always recognized as such, occurs in 

 Scotland at several other localities ; at Bowling quarry and at 

 Cochua near old Kilpatrick (as also, I am informed, at Bishop- 

 town), it assumes an appearance very different from its usual 

 aspect. It is here associated with Laumoutite, the sheafy variety, 

 and dark green talc, the matrix being highly magnesian in its 

 immediate vicinity. It occurs in spheres imbedded in the rock; 

 these are white at the centre, but of a fine green at the circum- 

 ference, apparently from the radiating crystals penetrating the 

 matrix. The specimens from this locality have been sold as 

 Stellite, which (see Phil. Mag. for April 1855) has been shown 

 to be Pectolite, and Dr. K. D. Thomson gave it the latter name 

 to Mr. Greg. Its analysis afforded, — 



Silica .... 48-033 



Alumina . . . 25-261 



Oxide of iron . . '865 



Lime .... 2-313 



Magnesia . . . '403 



Soda 13-975 



Water .... 9-723 



100-573 



A single colourless specimen, which I myself obtained at Bow- 



* Silica 47-4 



Alumina 26-9 



Soda 16-2 



Water 95 



