pyritous

As to the size of a pyritous mass necessary to produce in this manner a large nugget, it is by no means considerable.

Getting Gold: a practical treatise for prospectors, miners and students

When the sulphur contents of pyritous ores are sufficiently high, and after the ore has been initially fired with auxiliary carbonaceous fuel, it is unnecessary, in a properly designed roasting furnace, to add fuel to the ore to enable the heat for oxidation to be obtained.

Getting Gold: a practical treatise for prospectors, miners and students

This nugget is very irregular in shape, fretted and chased as though with a jeweller's graving tool, showing plainly the shape of the pyritous crystals on which it was formed while the interstices were filled with red hematite iron just as found in artificially formed nuggets on a sulphide of iron base.

Getting Gold: a practical treatise for prospectors, miners and students

Fossil wood with _Teredo antenautæ_ is also met with, and pyritous casts of univalve and bivalve shells.

Journal of the Proceedings of the Linnean Society - Vol. 3 Zoology Various

A forty per cent pyritous or other sulphide ore should be roasted in a revolving furnace in thirty to forty minutes, and without any auxiliary fuel.

Getting Gold: a practical treatise for prospectors, miners and students

It follows, then, from what has been previously affirmed, that there will be a reduction of gold by these nodules, and that the metal thus reduced will be firmly attached to them, at first in minute spangles isolated from each other, but afterwards accumulating and connecting in a gradual manner at that point of the pyritous mass most subject to the current until a continuous film of some size appears.

Getting Gold: a practical treatise for prospectors, miners and students

According to the original size of the pyritous mass, the protection it receives from the action of oxidising substances other than gold, the strength of the gold solution, length of exposure to it, the rate of supply and velocity of stream, will be the size of the gold nugget.

Getting Gold: a practical treatise for prospectors, miners and students

Professor Newbery, who made many valuable suggestions on the subject, says, speaking of gold in pyritous lodes:

Getting Gold: a practical treatise for prospectors, miners and students

"The _magistral_ is a mixture of pyritous copper and sulphuretted salt, roasted for some hours in a reverberating oven, and slowly cooled"

The Philippine Islands, 1493-1898 — Volume 20 of 55 1621-1624 Explorations by early navigators, descriptions of the islands and their peoples, their history and records of the catholic missions, as related in contemporaneous books and manuscripts, showing the political, economic, commercial and religious conditions of those islands from their earliest relations with European nations to the close of the nineteenth century. James Alexander Robertson 1906

~Alum~ is manufactured from the pyritous shales of the Mianwálí district, the annual output being generally about 200 to 300 tons.

The Panjab, North-West Frontier Province, and Kashmir James McCrone Douie 1894