496 Transactions. — Geolorjy. 



closed tube it decrepitates slightly, blackens and gives off water having an 

 alkaline reaction ; there is also a slight empyreumatic odour evolved. 



Pitch Opal. — Dunstan. 

 Brown, variegated, light and dark shades. Hardness about 6. When 

 heated in closed tube gives off water, blackens and emits empyreumatic 

 odour ; the condensed water has an acid reaction, and on evaporation 

 leaves a carbonaceous residue which blackens on ignition ; breaks with a 

 well-marked conchoidal fracture. Contains iron. 



Opal Jasper. — Near Duuedin. 

 A prettily marked ornamental stone, the predominant colours bieng red- 

 brown, blue-grey, and opal-white. Hardness about 6. 



Hyalite. — Bell Hill, Dunedin. 



Mammillated, colourless ; opaque white in part, lining cavity in vesicular 



grey trachyte. 



Quartzite. 



An altered or metamorphosed sandstone, containing fragment of fossil. 



Siliceous Sinter. — Hot Springs, Waikato. 



In stalactitic forms ; opaque white ; somewhat tender and friable ; when 



heated in closed tube, gives off water having a neutral or but faintly 



acid reaction, also emits a slight empyreumatic odour; cracks and breaks up 



into small fragments. This deposit, in common with other similar ones, 



does not consist of pure silica ; but contains some alumina, iron, lime, 



alkalies, etc. 



Jasper. — Clutha, Dunstan. 



Kolled nodule, dark reddish brown with veins of white quartz. 



Jasper. — Clutha. 



Very impure. 



Hornblende. '■'• — Lake McKerrow. 



Massive ; cleavage planes fairly well marked. 



Hornblende. — West Coast. 

 Massive ; large confused crystals ; greenish- black colour. 



Hornblende. — Kakanui Mountains. 

 Fragment of a large crystal : well-marked cleavage planes ; black. 



Hornblende.- — Dun Mountain. 

 Labelled "amorphous hornblende," shows a jointed structure; breaks 

 with a subconchoidal fracture ; has a somewhat greasy feel like serpentine. 



Diallage. — Lake McKerrow. 

 Foliated and confused masses of crystals ; colour green ; lustre not well- 

 marked. 



* Eep. N.Z. Esh., 1865, p. 438, 



