64 THE VICTOKIAN NATURALIST. 



of radiating crystals of Arragonite,. about half a pound in weight, 

 were found on the slopes." The records above indicated are also 

 referred to by Mr. J. A. Atkinson in his " Locality List of 

 Victorian Minerals;" hence, in view of the present communication, 

 it seems necessary that these records should be cancelled. 



The first suspicion that the mineral was not Arragonite came 

 from a test of its hardness, this feature being altogether too high 

 for that mineral; then a more critical blowpipe examination proved 

 undoubtedly that the mineral was a Zeolite belonging to the 

 Natrolite group. 



Description. — Mineral opaque white, to clear, transparent, and 

 glassy ; lustre vitreous wliere distinctly crystalline, but silky where 

 opaque and fibro-crystalline ; streak, white ; hardness, 6 ; specific 

 gravity, 2.167 to 2.17; tenacity, in mass tough, in splinters 

 brittle; fracture, splintery; fusibility, 3.5; form, more or less 

 hemispherical rosettes, ranging from about an inch to more than 

 three inches in diameter, composed of radiating crystals. The 

 greater portion of these rosettes is opaque milky white, but 

 near the outer circumference the glassy crystals become distinct. 

 The system of crystallization is rhombic, and the common form 

 hitherto identified consists of a combination of an elongated right 

 rhombic prism with a squat right rhombic pyramid for termina- 

 tion. No cleavage apparent, but the crystals commonly show an 

 uneven transverse fracture. 



Composition. — Essentially a hydrated silicate of alumina, soda, 

 and potash, with a little lime. The exact analysis — for which I 

 am much indebted to Mr. E. O. Thiele, my assistant at the 

 Working Men's College — is given below, and I take tiiis oppor- 

 tunity of thanking that gentleman for his trouble, for without his 

 assistance in this respect this paper would have been delayed for 

 some considerable time. 



SiO. 

 ALO. 

 CaO' 

 Na, O 

 K, O 

 H, O 



101.168 



Blowpipe Characteristics. — Flame colouration indicating sc- 

 dium, with cobalt glass the potassium flame is very distinctly 

 seen ; in the tubes the mineral becomes opaque white, losing its 

 lustre, and yields water without intumescence, and the residue is 

 easily crushed between the fingers to powder ; on charcoal alone 

 the mineral in small fragments fuses slowly, its fusibility being 

 above that of Garnet but lower than Actinolite — the fusion is 



