Sterling silver, also called fine silver, is a beautifully lustrous cool-toned precious metal favored in fine jewelry among other products. The most reflective of all metals (excluding mercury), sterling silver looks stunning by itself and brings out the best hues in an array of colorful gemstones.
Sterling silver can be polished to a higher sheen than platinum. In fact, Ag, the chemical symbol for silver, comes from a word that means “white and shining.” The surface of silver can boast that shiny, polished appearance, or can be brushed, satin, matte, sandblasted, antiqued or oxidized (chemically blackened).
In order to be called sterling silver, a metal must be made up of a minimum of 92.5% pure silver and 7.5% alloy (meaning other metals), including but not limited to copper and nickel. The alloy is added to pure silver to make the metal more durable, tougher and harder. Sterling silver is designated a fineness of “925.” Pieces with sterling silver may be marked “sterling.”
Finishes on Sterling Silver
Finishing, or plating, is a common treatment with sterling silver. Popular types of plating are rhodium plating, gold plating and anti-tarnish plating. Plating is used to extend the life and sheen of the jewelry. After sizing or buffing a piece of jewelry with a machine, it must be re-plated to restore the finish.
Caring for Sterling Silver
Sterling silver becomes tarnished as the result of a natural chemical process that occurs when sterling silver is exposed to chemicals in the air, rubber, wool and latex. Humidity also plays a role in accelerating tarnishing. It's easy to keep your sterling silver sparkling, though, by taking a few steps to prevent tarnish and other wear and tear.
Found all over the world, agate has been creatively striped by nature. It is a type of chalcedony quartz that forms in concentric layers of colors and textures. Each individual agate forms by filling a cavity in a host rock. As a result, agate often is found as a round nodule with concentric bands like the rings of a tree trunk. Tiny quartz crystals called drusy (sometimes spelled as druzy) often form within the stone, adding to its beauty and uniqueness. Agate is a hard stone, within the range of 7.0-9.0 on the Mohs Scale.
In 1497, the mining of agate in the Nahe River valley in Germany gave rise to the cutting center of Idar-Oberstein. When the Nahe agate deposit was exhausted in the nineteenth century, Idar cutters started to develop the agate deposits of Brazil, discovering Brazil's rich deposits of many other gemstones. A famous collection of two to four thousand agate bowls, accumulated by Mithradates, King of Pontus, shows the popularity of agate at the time. Agate bowls were also popular in the Byzantine Empire. Collecting agate bowls became common among European royalty during the Renaissance and many museums in Europe, including the Louvre, have spectacular examples.
Although the small town of Idar-Oberstein is still known for the finest agate carving in the world, today Idar imports a huge range of other gem materials from around the world for cutting and carving in Germany. Cameo master carvers, modern lapidary artists and rough dealers flourish there, exporting their latest gem creations. It is an entire industry that grew from the desire for agate products during the Renaissance.
Agate was highly valued as a talisman or amulet in ancient times. It was said to quench thirst and protect from fevers. Persian magicians used agate to divert storms. Today, some believe that agate is a powerful emotional healer and helps people discern the truth.