210 RECORDS OF THE ADSTRALIAN MUSEDM. 



A curious form of snlpliur from near Traitor's Head, Erromango, is 

 in the Musetiin collection. It consists of hollow spherules, measuring up 

 to three mm. in diameter, which liave no doubt been formed by gas 

 bubbles when the sulphur was in a molten state. Similar hollow spheres 

 of sulphur have been described by Ohashi, from the crater lake of the 

 volcano Shirane, Province Kozuke, Japan. ^* The Erromango spheres are 

 usuall}^ perforated by a small circular puncture, with a slightly raised 

 rim, through which the imprisoned gas doubtless escaped. Some have a 

 stalk, or a globular wart, evidently formed by the gas pressure forcing 

 out the wall of the spherical shell at a weak spot. The surface of the 

 spherules has a glazed appearance. 



SPHALERITE. 



Spring Creek, Buugonia, N.S.Wales. 



(PI. xli., figs. 3, 4.) 



Sphaleiite is of common occurrence in mineral veins at various 

 Australian localities, but it is seldom found in good crystals. The specimen 

 described here was brought under my notice and subsequently presented 

 to the Museum by Mr. Combe. In our collection there was previously a 

 large hand specimen from this local it}', consisting of massive sphalerite, 

 with a few indistinct crystals in association with ciystallised quartz, 

 galena, and chalcopyrite. The sphalerite is almost black externally, but 

 on cleavage it shows an amber colour. 



The figured crystal is a doublet on the tetrahedral face (spinel law); 

 the two segments interpenetrate and are elongated parallel to the tetra- 

 hedral axis, so that the ciystal is pseudo-hexagonal in section, the hexagon 

 being formed by the faces of the dodecahedron. The only forms present 

 are tlie tetrahedron and the dodecahedron, the former predominating. 

 Foi- measurement the crystal was mounted on the goniometei' with a 

 tetrahedral face polar. The faces of the tetrahedron are dull and give 

 poor reflections, but the dodecahedron is brilliant. 



i-i Oliashi — 1. .11111. Akita Miiiiuif Collow. No. 1, ISUy. 



