GOLD NUGGETS AND GOLD

Tuapeka Times, Volume III, Issue 206, 11 January 1872, Page 6

GOLD NUGGETS AND GOLD

(From the British Trade Journal.)

Gold being so much softer tlun quartz, its particles, after being subjected to the same degree of afctritior, ought be vastly smaller; although ot greater toughness than quartz, and possed of ductility and tenacity which qu rti wholly wants, it is very sof% and, under the inlluence of the attrition from running water and its accompaniments, ought to be pounded aud torn into the minutest fragments; Ini* this is not so. T.iereis, moreover, a marked difference in the appearance of the gold dust in different drifts in^ different countries- In some it is liko^ dust or sand, ia others it is like scales, if subjected to the same influence in all, there seems no reason why tho same shape should not obtain in all. In any and every view we think it caunot be disputed that degradation must have had some share in the work. The general similarity between gold, producing districts, by which a Cali-> foruim miner cculd detect a likely spot for geld in Austrlia or Kildonan, probably depends rather on the character of the mountains of which the gold has come than on the mode of production of the manufactured dust. We imagine that the truth will be found to be that the result is referable to two causes, only one of which may, in some cases, have been present, in others both ; tbe first, tho ordinary process of degradation and grindiug the r >cks to fragments ; the other, as suggested by Mr. Selvvyn, the Government ' geologist of Victoria, the gold has been taken up in solution by the water permeating the gold-bearing rocks, and in passing through the drift, in which minute particles of gold lay, it has, from some cause, become decomposed, and the gold held in solution been precipitated and deposited around the most congenial nuclei^presented to it, which would undoubtedly [ generally be the particles or pieces of - reef gold, or any metallic substances for which it had an affinity. From various experiments it would appear tbat organic matter is the nocessarv chemical agent for decomposing a solution of the chloride of gold, in order to precipitate the gold as a coherent coating round a nucleus. It is to be observed that organic substances^ such as fragments of wood, roots of trees, &c , occur abundantly in the gold drifts of Australia. If water holding gold in solution circulates through the rocks and drifts, all the conditions necessary for the production of gold dust and nuggets by deposit are prespnt -Does the water so circulating now hold gold in solution ? One would think it would not' be difficult for a chemist in Australia or California to' determine the fact by direct experiment ; but it docs not appear that it bas been tried. It mast, be admitted that tbe faefcthat gold may be greatly purified by dissolving and reprecipi taring it, is very suggestive of the generally higher standard of aliav'ial over reef gold being due to a, similar cause.