Greetings August babies and lovers of all things sparkly! This month we explore Peridot, Sardonyx, and the newly added Spinel. Yes, that’s right. August joins June and December in the exclusive Three Birthstone Club!
What is peridot?
Peridot is the rare gem-quality variety of the common mineral olivine, which forms deep inside the earth’s mantle and is brought to the surface by volcanoes.
In Hawaii, peridot symbolizes the tears of Pele, the volcano goddess of fire who controls the flow of lava. Rarely, peridot is also found inside meteorites. Cool, right?
Peridot’s signature green color comes from the composition of the mineral itself—rather than from trace impurities, as with many gems. That’s why this is one of few stones that only comes in one color, though shades may vary from yellowish-green to olive to brownish-green, depending how much iron is present. Source: www.americangemsociety.org
Where is Peridot Found?
Most of the world’s peridot supply comes from the San Carlos Reservation in Arizona. Other sources are China, Myanmar, Pakistan and Africa.
Peridot jewelry dates back as far as the second millennium BC. These ancient Egyptian gems came from deposits on a small volcanic island in the Red Sea called Topazios, now known as St. John’s Island or Zabargad. Ancient Egyptians called peridot the “gem of the sun,” believing it protected its wearer from terrors of the night. Peridot is also said to bring the wearer power and influence.
Some historians believe that Cleopatra’s famed emerald collection may have actually been peridot. Through medieval times, people continued to confuse these two green gems. The 200-carat gems adorning one of the shrines in Germany’s Cologne Cathedral were long believed to be emeralds as well, but they are also peridots. Source: www.gia.edu
How to Buy Peridot
Peridot can be rated with the same criteria as diamonds—using color, clarity, cut and carat weight to determine value.
The finest peridots have a lovely lime green hue without any hints of brown or yellow. Quality gems have no inclusions visible to the naked eye, though dark spots may be evident under a microscope. When you look closely, due to double refraction, you may see two of each facet on a peridot.
How to Care for Peridot Jewelry
Peridot is 6.5 to 7 on the Mohs scale, meaning itt has fair to good toughness. Peridot is durable enough for jewelry wear but should be worn with some care so as not to scratch it or subject it to hard blows that can fracture it.
Rapid or uneven heat can cause peridot to fracture. Peridot is stable to light but is easily attacked by sulfuric acid, and less easily by hydrochloric acid. It can also be attacked over a long period of time by acid perspiration.Warm, soapy water is the best method for cleaning peridot. Ultrasonic and steam cleaners are not recommended. Source: www.gia.edu
What is Sardonyx?
Sardonyx combines alternating layers of sard and onyx—two types of the layered mineral chalcedony—to create a reddish zebra-striped stone with white bands.
Its name, similarly, combines sard (referencing the ancient Persian city, Sardis, in present-day Turkey, where the red stone was found) with onyx (from the Greek word of the same spelling, which meant “nail or claw.”) Source: www.americangemsociety.org
Where is Sardonyx Found?
The finest examples of sardonyx, which display sharp contrasts between layers, are found in India. Other sources include Brazil, Germany, Czechoslovakia, Madagascar, Uruguay and the United States.
Sardonyx has been popular for centuries, dating back to the Second Dynasty of Egypt more than 4,000 years ago. Ancient Greeks and Romans went to battle wearing sardonyx talismans engraved with images of heroes and gods like Hercules and Mars. They believed the stone could harness the bravery of those figures, granting them courage, victory and protection on the battlefield. Sardonyx was a popular stone for Roman seals and signet rings that were used to imprint wax emblems on official documents—due to the fact that hot wax doesn’t stick to this stone. Source: www.americangemsociety.com
During Renaissance times, sardonyx was associated with eloquence. Public speakers and orators wore it to aid clear thinking and communication. Because of its attractive banding, sardonyx has long been used to fashion cameos (carved raised figures) and intaglios (the reverse of cameos).
How to Buy Sardonyx
The qualify factors of sardonyx are not as clearly defined as other gems, so it’s a good idea to have a certified gemologist choose stones for you!
The most attractive sardonyx shows a high contrast between reddish layers of sard stone and white bands of onyx. Sardonyx is widely available and moderately priced in sizes up to 10 carats.
Artificial and imitation sardonyx has been produced from common chalcedony and plain agate. Some gems are also stained with iron oxide pigment or treated with nitric acid to enhance color. These enhancements make stones less valuable than natural sardonyx, so watch for imitations when buying these gems. Source: www.americangemsociety.com
How to Care for Sardonyx Jewelry
Sardonyx measures 6.5 on the Mohs hardness scale, making it a less ideal choice for rings and bracelets and other jewelry that can receive knocks and scrapes. It can be cleaned with warm soapy water and a soft brush or an ultrasonic or steam cleaner may can be used if you’re certain the stone is not imitation or treated. Avoid prolonged exposure to extreme heat or chemicals that may damage the stone. To avoid scratching, always store sardonyx in a fabric-lined boxed or wrapped in a soft cloth.
What is Spinel?
Spinel was added to the birthstone lineup for August in 2016. Spinel, like garnet and diamond, is singly refractive, with the same physical properties in all crystal directions. It belongs to the cubic crystal system, and its characteristic crystal shape is an octahedron, which looks like two back-to-back pyramids. Spinel offers a range of hues, from orange to intense “stoplight” red, vibrant pink, and all shades of purple, blue, and violet through bluish green. Intense reds and pinks are caused by traces of chromium. The higher the chromium content, the stronger the red hue. Orange and purple stones owe their color to a mixture of iron and chromium. Violet to blue spinel can be colored by trace amounts of iron, and vibrant blues owe their saturated color to trace amounts of cobalt. Source: www.gia.edu
Where is Spinel Found?
Significant deposits of spinel have been found in Cambodia, Myanmar, Sri Lanka and Thailand. It has also been found in Afghanistan, Australia, Brazil, Madagascar, Nepal, Nigeria, Tadzhikistan, Tanzania and the U.S.
How to Buy Spinel
Vivid red is the most desirable color of spinel gemstones, followed by cobalt blue, bright pink and bright orange. The more affordable stones are often those with paler colors, like lavender. You may also find spinel in black, violet blue, greenish blue, greyish, pale pink, mauve, yellow or brown. So many choices!
When shopping for spinel, a good quality stone should have no visible inclusions. The more inclusions, the less valuable the stone. Spinel can be found various cuts, like octagons, trillions, squares, rounds and fancy shapes, like ovals, pears and cushions.
How to Care for Spinel
Spinel ranks 8 on the Mohs scale and has good toughness, making it a durable gem for jewelry. While ultrasonic cleaners and steam cleaners are usually safe, certain inclusions like fractures could pose a potential problem. It’s always safe to clean spinel with warm soapy water. As always, Bremer Jewelry is happy to professionally clean and inspect your jewelry for FREE!