C. Palache — Crocoite from Tasmania. 389 



Art. XLVI. — Crocoite from Tasmania; by Charles 

 Palache. 



Through the kindness of Mr. Stephen A. Douglas of San 

 Francisco, the writer came into possession some time since of 

 specimens of crocoite from Tasmania representing, so far as his 

 information extends, a new or undescribed locality for this min- 

 eral. Of the two specimens available for study one is now in 

 the mineral cabinet of the University of California, the second 

 in the writers possession. They consist of masses of crocoite 

 crystals clustered upon bases of lamellar limonite, each mass 

 measuring several inches in diameter. The mineral occurs in 

 a silver-bearing lead deposit known as the Adelaide mine on 

 Mt. Dundas, west coast of Tasmania ; but of the nearer geo- 

 logical relations unfortunately no information is at hand. It is 

 said to occur in considerable abundance, a statement borne out 

 by the appearance of these specimens and the many others in 

 Mr. Douglas's possession. Besides the limonite there is no 

 trace of gangue or wall rock nor are there any other lead min- 

 erals such as might be expected to accompany the crocoite. 



The crystals are of a light hyacinth red color, quite translu- 

 cent and with adamantine luster. They vary in size from 

 minutest needles to prisms of 2 cm length and 3 mm diameter. 

 The habit is prismatic and the crystals are never doubly termi- 

 nated, being attached at one end to the limonite. The larger 

 crystals are often cavernous, giving rise to hollow prismatic 

 forms. As is usually the case with crocoite, the crystal planes 

 are even and brilliant, giving good reflections on the goniome- 

 ter. The faces of the prism zone are, however, strongly stri- 

 ated parallel to the prism edges and this renders the identifica- 

 tion of some forms doubtful. 



Four crystals were subjected to measurement and showed 

 the following forms, most of which were present on each crys- 

 tal. The letters used are those of Dana. 



m 



(110) 



I 



k (101) 



l~% 



f 



(120) 



i-2 



z (Oil) 



l-i 



d 



(210) 



i-2 



w (012) 



Iri 



*S 



(103-0) 



HF 



y (021) 



2-i 



*T 



(530) 





t (in) 



-1 



b 



(010) 



v (Til) 



1 



c 



(001) 











The following table shows some of the measurements and 

 the angles calculated from Dauber's elements. 



