Dissemination of Gold
Dissemination of Gold.—The wide distribution of gold in minute quantities throughout the world was pointed out by W. E. Dubois, an Assayer in the United States Mint, in 1861, and is further attested by a large number of specimens now in the Percy collection. These consist of small specks of gold of different sizes which […]
List Minerals Associated with Gold
To know what type of rock is gold associated with you must see that the minerals most common in placer deposits are platinum, iridosmine, magnetite, iron pyrites, ilmenite, zircon, garnets, rutile and barytes; wolfram, scheelite, brookite and diamonds are less common. Diamonds are associated with gold in Brazil, and also occasionally in the Urals and […]
How Gold Ore is Formed · Genesis
The origin of mineral veins, including those in which gold is contained, has long been discussed by geologists. The old theory that the quartz of veins was originally in a molten condition and was ejected from below into fissures is no longer maintained, although in 1860 H. Rosales brought forward evidence in its favour as […]
Where is the Gold in the World
To understand the Geographical Distribution of Gold and where is the most gold in the world you must start with the British Isles, where gold is found in some of the streams of Cornwall and in lodes and river gravels near Dolgelly and in other parts of Wales, in Sutherlandshire, and near Leadhills in Scotland, and […]
Gold Oxides
Aurous Oxide, Au2O This gold oxide is prepared by decomposing aurous chloride, AuCl, or the corresponding bromide by potash in the cold (Berzelius) when a violet precipitate forms, which is blackish when moist, but greyish when dry. When freshly precipitated it is soluble both in alkalies and in cold water, forming an indigo blue solution, with […]
Solubility of Gold
Gold is readily soluble in aqua regia, or in any other mixture producing nascent chlorine, among such mixtures being solutions of: nitrates, chlorides, and sulphates — e.g., bisulphate of soda, nitrate of soda, and common salt; chlorides and some sulphates—e.g., ferric sulphate; hydrochloric acid and potassium chlorate; bleaching powder and acids, or salts such as […]
Types of Placers
Perhaps the best known schemes for the classification of gold placer deposits are those by Jenkins and Brooks, the former being based on conditions of deposition and the latter on present position of the deposit. The field engineer should acquaint himself with these schemes, particularly that by Jenkins which has been developed in some detail. For […]
Gold Placer Geology
The source of gold or other minerals found in a placer may be one or more of the following: a. Lodes or mineralized zones. b. Erosion of pre-existing placer deposits. c. Low-grade auriferous conglomerates or glacial debris. d. Magmatic segregations and associated basic rocks. e. Regional rocks containing scattered particles of valuable mineral. a. Lodes: Although […]
Anthracite Basins Structural Geology
In earlier years, the custom prevailed of regarding the anthracite basins as cases of folding with slight development of faulting. Folding is so pronounced and, in the eastern and western Middle Fields, at times so violent, that the inference was a natural one and led to the widespread impression that practically all the disturbances of […]
Managing a Mineral Discoveries
Sampling and Assaying A prospector sometimes fails to reap the full advantage, or even any advantage, from a discovery, because of his manner of handling it. The first step is to ascertain the value of the mineral deposit; in most cases, this must be done by having assays made. As a preliminary, a selected sample […]