The common ore is native copper, often associated with native silver, the two remaining, chemically, quite distinct. Some masses of copper occur that are too large to handle and must be cut by cold chisels, a method that costs more for labor than the value of the metal.
It is advisable first of all to examine the ore for visible gold and silver, the presence of which might influence the choice of a method of treatment. If no gold or native silver can be seen in the rock, take a representative sample of about 300 grams and grind it up to pass a No. 30 sieve.
Silver jewelry manufacturers can verify the purity of the silver they purchase to make jewelry as well as monitor their own process in alloying pure silver. Jewelry dealers can determine silver purity on the spot before they purchase coins, jewelry or "pure" silver
How to Calculate the Specific Gravity of a Coin  [ENG] Manual Why? To Know the specific gravity of a coin it is useful for the determination of its gold or silver content, this is an useful information to discover some fakes or to study the composition of certain coins.
The goal of assaying and testing any potential gold and silver bearing materials is to determine their metals content. While it is sometimes possible to look at a sample and guess its possibilities, more often than not, in order to have an accurate idea of how valuable in ore is it must be analyzed.
On silver necklaces, silver bracelets, and silver anklets, you can typically find this hallmark on the clasp. On silver rings, the hallmark is almost always on the inside of the band. For flatware, look for a "sterling" stamp on the underside of the utensil.
Classification of Ores. In fluxing ore for gold and silver, first determine the nature of the sample submitted for assay. Three different classifications may be made in the preliminary examination of ores; first, pure quartz (very glassy or vitreous); second, no quartz (plastic and free from grit); third, a mixture of these two extremes which may be assumed to be the average as to siliciousness.
Sterling silver is 92.5% pure silver, which is why it is so much more expensive than plated items. Sterling silver can be melted and the pure silver recovered rather inexpensively. Sterling silver is traded in troy ounces, a troy ounce being equal to 31.2 grams.
Silver mining is the resource extraction of silver by mining.. Silver is found in native form very rarely as nuggets, but more usually combined with sulfur, arsenic, antimony, or chlorine and in various ores such as argentite (Ag 2 S), chlorargyrite ("horn silver," AgCl), and galena (a lead ore often containing significant amounts of silver).
We are often asked by some of our readers how they can determine the authenticity of the silver they come across in their precious metal endeavors. While there are many methods of making this determination, for this post we list what we think are the three quickest and easiest.