Page:Transactions NZ Institute Volume 15.djvu/505

Halloysite, …Al S̈i + 4 Ḣ.—The occurrence of this mineral in decomposing basalts around Dunedin is mentioned by Dr. Hector (Jurors' Rep. N.Z. Ex., 1865, p. 438), and a specimen from the Water of Leith is described by Professor Liversidge (Trans. N.Z. Inst., vol. x., p. 499) as follows:—"An opaque white earthy substance, soft and soapy; associated with it is a little black halloysite; when immersed in water it gives off airbubbles rapidly, accompanied by a singing sound; falls to pieces and becomes translucent on the thin edges; breaks with a conchoidal fracture; adheres strongly to the tongue; yields to the thumb-nail, and affords a shining streak; possesses an earthy smell." A sample of an impure form from Scinde Island, Napier, where it occurs in considerable quantities (Col. Mus. and Lab. Rep., vii., p. 18), was forwarded to the Museum in 1872, and had the following composition:—

the high proportion of silica being due to the presence of grains of free quartz, which constitute the principal impurity. A specimen from the Bay of Islands was forwarded by Mr. J. Williamson in 1874, and is of a yellowish-brown colour, and very fine grain; three specimens from the Drury and Hunua Ranges were forwarded by the Hon. H. Chamberlin in 1875, and a specimen collected from Whangaroa Harbour, by Mr. A. McKay, during the same year.

Fuller's Earth.—Specimens from Great Barrier Island and the Hot Springs, were exhibited at the Dunedin Exhibition of 1865, by the Auckland local committee, and are mentioned (Jurors' Rep. N.Z. Ex., 1865, p. 253).

Palagonite, (…Al, …Fe) S̈i³ + 3 (Ċa, Ṁg, Ṅa) S̈i + 10 Ḣ.—The occurrence of this mineral as angular fragments in palagonite tufas is mentioned by Dr. v. Haast (Jurors' Rep. N.Z. Ex., 1865, p. 257), at Harper Hills, near the Selwyn, and at Two Brothers, Ashburton, as also another variety changing insensibly into a pitch opal, enclosing leaves and stalks silicified, in the same localities. A specimen from Taipo Hill, Otago, was forwarded in 1868 by Mr. C. Teschmaker, where it occurs as a large seam 60 feet thick, running in the direction of a limestone quarry. Its characters, as described by Mr. Skey, are—massive; colour, black; hardness, 4.5; somewhat, friable; is