Silver is formed when hot water flows through the veins of rocks, usually deep inside an ore. It is mined in places like Mexico, Germany and Peru, but also in states like Michigan, Nevada and Arizona. Once silver is removed from the ore, it is melted down and has many uses, such as in money, photography, batteries, jewellery and silverware. Types of silver differ depending on how much pure silver they contain.
Pure silver is defined as containing more that 99.5 per cent silver. In its pure form, silver is extremely soft, so it is not used to make full pieces of jewellery or larger pieces such as silverware or housewares. It is too malleable in this form and cannot hold its shape. It is good, however, for making wire in its pure form, and this wire can be bent again and again without hardening. This makes it useful for intricate trim work and jewellery inlays.
Sterling silver is made by combining 92.5 per cent pure silver with 7.5 per cent of another metal, most often copper. Blending the pure silver with another metal, or metal alloy, helps improve the silver's quality for items such as jewellery, pitchers or teapots. Any silver item that is designed to be as pure as possible, but also needs to retain its same shape, can best be made from sterling because the mixture makes it more durable. Most sterling silver pieces will be marked with the number 925 somewhere on the piece. This lets the buyer know that it is sterling, standing for the 92.5 per cent silver it requires.
Sterling Silver Overlay
Sterling silver overlay is used in making items that need the durability of another metal but want the appearance of sterling silver. A stronger base metal is used to make a platter, for example. Then a thick layer of sterling silver is layered onto the piece. This results in a sterling item that is not solid sterling and will not bend. This is useful in making many durable silver items such as silverware. The layer of sterling is thick enough in an overlay that it can be engraved into, and it will even tarnish like full sterling silver. Silver overlay items will often be marked with the words "silver overlay."
Silver plate is created by adhering a very thin layer of silver onto another metal. Unlike sterling silver overlay, which is done to create durability, silver plating is often done to save money, creating jewellery from less expensive metal alloys and giving it the appearance of silver. Silver plate is thin enough that engraving the item must be done on the base metal, which will show through the layer of silver. Silver plate cannot be cleaned with silver cleaner to resist tarnish because the layer will erode. Silver plate will be marked with the words "plate" or "silver plate."