24 ' INK'KOORDKl* AND OIHKH MINERALS 



28 GiBBSiTE. — [Hydrate of ahnniniuin.') 



Apparently abundant in botryoidal masses, associated 

 with native copper and earthy lode-material. It 

 varies in colour from clear pellucid glassy to pale 

 green, and more rarely to golden yellow with a 

 bronze lustre. It decomposes to a white powder. 

 Rio Tinto Mine, Savage River. 



29 Gmelinite. — {Hydrous sodium, calcium, and alu- 



miniuTn silicate.^ 



3^ fine lot of perfect crystals of this zeolite have been 

 obtained loose and coating a vugli in Tertiary 

 basalt at Bell Mount. Middlesex. 



30 Hauynite. — {Sodiu7n, calcium, and aluminium or- 



thosilicate with sodium sidphate.) 



In micro-crystals sparingly in the fayalite-melilite 

 basalt f]'om One Tree Point, near flobart. 



31 Hematite. — {Sesquioxide of iron.) 



At Zeehan this occurs pseudomorphous after cubical 

 pyrites. (R. F. Waller.) 



32 Histeixite. — (Sulphide of antimony and bismuth.) 



An apparently new substance occurring in radiating 

 groups of prismatic crystals, which are occasionally 

 in confused bunches, and commonly stained ex- 

 ternally with a dark brown coating. The crystals 

 are orthorhombic, with acute but indistinct ter- 

 minations, and striated longitudinally. They 

 sometimes reach over 2 in. in length by | in. in 

 width. Slightly sectile, with a hardness of about 

 2. Lustre eminently metallic, shining on fresh 

 crystalline surfaces. Colour and streak, steel-grey. 

 When massive, it presents a foliated structure, and 

 tarnishes to blue and purple iridescent colouration. 

 The crystals occurred interpenetrating a vugh 

 from a bedding of a mixture of iron and copper 

 pyrites. It was found in a somewhat massive 

 body of tetrahedrite, with which were associated 

 bismuthinite and pyrites, and appeared to te of 

 very exceptional occurrence. 



