Two Vintage Native American Road Runner South West Turquoise Sterling Silver Brooches. Estimated more than 50 yrs old. 925 Sterling Silver consisting of 92.5% silver and 7.5% copper. Tested Positive using Nitric Acid Chemical Scratch Test, Cloth Rub Test, and Magnet Test. Markings of 925 or Sterling stamp. The reason silver needs to be combined with other metals is that it is very difficult to make great designs with just pure silver, which is very soft and malleable. A bit of hardness has to be introduced by adding other metals such as copper. That is why jewelers are capable of making the most intricate an complex designs with 925 Sterling Silver. Silver is one of the most valuable elements next to gold. Mexico is the leading producer of silver, followed by the United States, Canada, Australia, Spain, Peru, and Russia. Many countries do not require their precious metal items to be stamped and therefore we test to ensure we accurately represent the product. For Size And Weight See The Last Photo If Not Written In This Description. All Photos Represent The Lot Condition. Please Read Our Terms And Conditions.