Onyx is a variety of chalcedony quartz that features a fine texture with a smooth black color. Some onyx can display white bands or ribbons against black or brown backgrounds. Mined in Brazil, India, California and Uruguay, most onyx today is color-enhanced to increase its depth of color. It ranks a 6.5 on the Mohs Scale and is an ideal stone for carving. In fact, it is a favorite material of lapidary artists.

Onyx was very popular with the ancient Greeks and Romans. The name comes from the Greek word “onux,” which means fingernail. Legend says that one day frisky Cupid cut the divine fingernails of Venus with an arrowhead while she was sleeping. He left the clippings scattered on the sand and the fates turned them into stone so that no part of her heavenly body would ever perish. In Greek times, almost all colors of chalcedony were called onyx. Later, the Romans narrowed the term to refer to only the black and dark brown colors, while the reddish brown and white onyx became known as sardonyx. Highly valued in Rome, sardonyx was especially used for seals because it was said to never stick to the wax. Roman General Publius Cornelius Scipio was famous for wearing sardonyx.

Worn during mourning in the Victorian age, onyx is now traditionally given as a 7th wedding anniversary gift. It is thought to increase happiness, intuition and instincts. The stone is also believed to cool the yearnings of love and decrease sexual desire.

Agate:

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 druzy (sometimes spelled as drusy) 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.

Necklace & Bracelet Clasp Types

Lobster Claw Clasp: As a traditional clasp style found in bracelets and necklaces, the lobster claw is generally reserved for heavier styles that may need added strength. The closure's shape is more oblong, similar to a teardrop shape, and is controlled by a tip that opens and closes the spring in the clasp. This type is also considered a more expensive finding that can add to the overall value of the jewelry piece.

Magnetic Clasp: The popularity of the magnetic clasp has greatly increased in recent years. It is a quick and easy way to secure jewelry while not having to fuss with a tiny clasp, which can be difficult if you have long fingernails, arthritic hands or other mobility challenges. A magnetic clasp relies on a strong internal magnet that works to pull both ends of the clasp together. In most cases, a magnetic clasp is used for light to medium weight jewelry pieces that do not put excessive stress on the magnet.

Slide Insert Clasp: This type of clasp is exactly as it sounds. With a box-like shape that is hollow on the inside, the wearer will slide the nearly-flat tab into the box until it clicks, indicating a secure closure. On some jewelry, a slide insert clasp will be accompanied by a side safety catch, which adds strength and security to the clasp. Although this type of clasp is found on both bracelets and necklaces, it is particularly popular on bracelet styles. These types of clasps are often reserved for more expensive jewelry.

Spring Ring Clasp: One of the most common closure types, the spring ring clasp is typically used for light to medium weight bracelets or necklaces. It is round in its design and features a small tip which controls the opening and closing of the spring. The circle then closes around another smaller loop or link at the other end of the strand.

Toggle Clasp: A toggle clasp is a narrow piece of metal, usually designed in the shape of a bar, which is then pushed through a circular ring to act as a fastener. Unlike the lobster claw or spring ring clasps, a toggle clasp is not controlled by a spring. The pretty design is less secure than other closure types, but is usually meant to be a big part of the design and is meant to "show". The clasp is an attractive way to secure a chunkier link bracelet or necklace.