MISIS "Sumatra" 18K Gold Plated Simulated Diamond & Green Agate Tiger Earrings

On the Mohs Scale, which measures the hardness of minerals, cubic zirconia is an 8.0 to 8.5. It is important to understand that hardness is not necessarily related to durability. Even though diamond is the hardest mineral (10.0 on the Mohs Scale), it can still be chipped or broken.

The only ways to tell the difference between cubic zirconia and diamond are by use of a thermal probe, by weighing the loose stone or by microscopic examination of surface features and inclusions. Cubic zirconia weighs approximately 65% more than diamond. Therefore, while a 6.25 mm round diamond weighs about 1.00 carat, the same size cubic zirconia weighs about 1.65 carats. If you know the weight of a cubic zirconia, you can figure out the diamond weight equivalent by multiplying the cubic zirconia weight by 0.6, or 60%.

Few natural diamonds on the market today are perfectly cut, and those that are cost much more than the usual diamond. Unleashing the fire, beauty and brilliance of a stone depends on its precise cut. Simulated diamonds are an excellent balance between quality, beauty and price.

Glossary

Brilliance: The white light leaving a jewel, traveling upward, which is visible to the eye. Brilliance is sometimes referred to as “sparkle.”

Dispersion: Flashes of rainbow colors. Also called “fire.”

Hardness: Resistance to scratching. The higher the number, the more resistant.

Luster: The shininess of a jewel.

Toughness: Resistance to breakage.

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 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.

Spinel:
The great imposter of gemstone history, many famous rubies have been found to actually be spinels. Perhaps the most famous of which is the Black Prince’s Ruby. Once worn by Henry V on his battle helmet, this 170.00ct red spinel is now set in the British Imperial State Crown. Another famous misidentification is the Timur Ruby, a 352.00ct red spinel now owned by Queen Elizabeth. This particular stone is engraved with the names of the Mughal emperors who previously owned it.

History is unclear whether these mistaken identities were merely accidents or clever substitutions of rubies for the less valuable spinels by dishonest jewelers. In Burma, spinel was recognized as a separate gem species in 1587, but the masquerade lasted for hundreds of years after that in most other countries.

Spinel carries a considerable amount of worth not only based on its history, but due to its brilliance and wide range of spectacular colors. When interpreted by the Greek, the word “spinel” means “spark” in reference to its beautiful sparkle. While a rich red is the most common color, spinel can be found in shades of pink, purple, green, brown or black. An exceptional color from Burma is a vivid hot pink with an orange undertone. Spinel can also come in a beautiful blue hue, sometimes called cobalt spinel, but this color is quite rare.

The main obstacle holding back greater recognition for spinel is rarity. Fine spinels are now more rare than the rubies they used to imitate. Strangely, however, they are also more affordable, since too rare can be a drawback because such few people have the opportunity to grow to love them. The most beautiful colors of the stone are mined in Myanmar (formerly Burma), but spinels are also found in Sri Lanka, Tanzania and Russia. They have a hardness of 7.5-8.0 on the Mohs Scale and are traditionally given as a 22nd wedding anniversary gift.

Earring Back Types

Butterfly Back: A double looped piece resembling a butterfly that fits over a post. Variations on this design are called push back clasps. The basic post and butterfly back are usually used for stud earrings and lighter weight drop earrings.

Hinged Snap Backs: This clasp features a hinged post that snaps into a groove on the back of the earring. It is commonly found on hoops. Sometimes the hinged post is curved to provide more room to fit around the ear, sometimes called a saddleback.

Hook Backs: This earring backing is simply a long, bent post that fits through the piercing. Hooks have several variations, most notably the shepherd's hook and the French hook. While thin wire hooks reduce the weight of long earrings, making them more comfortable, they aren't as secure as other clasp styles.

Lever Back: A hinged lever snaps shut against the curved post to form a closed loop around the ear lobe. This clasp is very secure and good for large or medium sized styles that drop just below the ear.

Omega: Also called French clips, this clasp has a straight post and a looped lever. The hinged lever closes around the post and is held against the ear with pressure. The omega clasp is the most secure clasp, especially for the larger, heavier earrings.

Screw back: This backing is a slight variation of the standard post and butterfly nut back. Instead of pushing on the back, the nut twists onto the threaded post. A screw back post design is often preferred for expensive diamond stud earrings that require increased security.