Page:Transactions NZ Institute Volume 15.djvu/489

Dolomite, Ċa C̈ + Ṁg C̈.—Dr. v. Haast mentions the occurrence of this mineral at the Malvern Hills (Jurors' Rep. N.Z. Ex., 1865, p. 256) interstratified with angitic greenstone, and it was collected by Dr. Hector in 1872 from Collingwood.

Pearlspar.—A specimen of this mineral was collected by Dr. Hector in 1878, from the Big Pump Shaft at the Thames.

Epsom-salt, Ṁg …S + 7 Ḣ.—Dr. Hector mentions the occurrence of this mineral on Murison's station in Otago (Jurors' Rep. N.Z. Ex., 1865, p. 438).

Taranakite.—This mineral, which is a double hydrous phosphate of alumina and potash, part of the alumina being replaced by ferric oxide, was first discovered by H. Richmond, Esq., at the Sugar Loaves, Taranaki, where it occurs as thin seams which occupy fissures in the trachytic rocks. It is described by Dr. Hector (Juror's Rep. N.Z. Ex., 1865, p. 423) as of a yellowish-white colour; amorphous and soft; readily fusible before the blowpipe, and in other respects resembling wavellite. It has the following composition:—

Phosphoric acid			35.05
Alumina			21.43
Ferrous oxide			4.45
Lime			.53
Potash			4.20
Soda			traces
Chlorine			.46
Sulphuric acid			traces
Insoluble in acid (silica)			.80
Water driven off at 212°	15.46	${\displaystyle \scriptstyle {\left.{\begin{matrix}\ \\\\\ \ \end{matrix}}\right\}\,}}$	33.06
{{{1}}}„ {{{1}}}„ {{{1}}}„ red heat	17.60
			100.00

and has a slight acid reaction.

Wavellite, …Al³ (symbol characters)² + 12 Ḣ.—Occurs as thin seams of a dark, yellowish-brown colour, hard, translucent, and infusible, traversing the taranakite in various directions, and is mentioned by Dr. Hector (Jurors' Rep. N.Z. Ex. 1865, p. 424).

Alunogene, …Al …S³ + 18 Ḣ, is mentioned by Dr. Hector (Jurors' Rep. N.Z. Ex., 1865, p. 438) as occurring in some of the brown coals. In 1867 a specimen was forwarded from Tuapeka by Dr. Halley, which proved to be nearly pure sulphate of alumina. It was colourless and well crystallized and completely soluble in water. The following analysis shows that its composition is—