Argentum content in native silver is not less than 97-99%. As you may know, both gold and native silver are formed mainly in hydro-thermal lode deposits. Constant interest to native ores is accounted for their extreme rareness and high value, for sure.
Native silver was discovered significantly later than silver ore. This white-coloured metal easily forms compounds with various chemical elements. Nowadays, due to its high chemical activity, there are almost no native silver deposits left.
The annual amount of the world commercial production of native silver is about 20,000 tons. Nearly half of this amount accounts for Chile, Mexico, China, and Peru.
The largest deposits for silver mining are also in the territory of Germany, Norway, Slovakia, Canada.
In nature, silver is encountered as large plates, silver dendrites, it can form small non-geometrical granules, filamentous and wiry formations. Large silver nuggets that weigh hundreds of kilos are very rare to find.