By Elsa Navarrete
For those of us living in the Northern Hemisphere, August is usually a favourite month filled with sun and fun. August is one of our favourite months because it has three gemstones appointed to it! And as you know, at Covett, the more the merrier. Why settle for one when you can have more?
This week we will start with the most popular known peridot. Peridot is the yellowish green to greenish yellow gem variety of the mineral olivine. Throughout history, peridot has often been confused with other gems such as topaz and emerald.
Peridot’s signature green colour comes from the composition of the mineral itself—rather than from trace impurities, as with many gemstones. That’s why this is one of few gemstones that only comes in one colour, though shades may vary from yellowish-green to olive to brownish-green, depending on how much iron is present.
This August birthstone was valued in many ancient and medieval cultures. It appeared in priests’ jewellery as early as the second century BCE and later in the chalices and churches of medieval Europe. The peridot birthstone has also been used for centuries as a protective talisman, shielding the owner from evil spirits and “terrors of the night”.
This August birthstone has also come to Earth via pallasite (made of nickel-iron and olivine) meteorites. Thousands of meteorites have hit the earth, many of them containing olivine, but only a few have had gem-quality peridot.
Though peridot is widely recognised for its brilliant lime green glow, the origin of this gemstone’s name is unclear. Most scholars agree that the word “peridot” is derived from the Arabic faridat, which means “gem;” however, some believe it’s rooted in the Greek word peridona, meaning “giving plenty.” Perhaps that’s why peridot was, according to lore, associated with prosperity and good fortune.
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 once symbolised the tears of Pele, the volcano goddess of fire who controls the flow of lava.
The Red Sea island of Topazios, a purported source of the name “topaz”, actually produced peridot. The Shrine of the Three Holy Kings in Germany’s Cologne Cathedral is decorated with 200 carats of gems that were believed to be emeralds but are, in fact, the August birthstone peridot. Some historians even speculate that Cleopatra’s famous emerald collection may have been comprised of peridot.
Though it is known as “the Evening Emerald” because of its sparkling green hue, peridot looks good any time of day.
- The biggest and most expensive peridot has come from Zebirget, Egypt.
- It is 311.78 carats
- Weighs 62.35 grams.
- On display in the Smithsonian Museum in the USA.
- Most of the world’s peridot supply comes from the San Carlos Reservation in Arizona. Other sources are China, Myanmar, Pakistan, and Africa.
- There is a Peridot Beach in Hawaii, where the sand shimmers a luminous green.
- Some peridot journeyed to Earth on meteorites
With a hardness of 6.5 to 7 on the Mohs scale of hardness, peridot is softer than many gems and cannot take hard wear, so it is not recommended for daily use in a ring. This August birthstone can also be damaged by some acids and even by long-term exposure to acidic perspiration. Cleaning peridot is a delicate process. Never use a steam or ultrasonic cleaner, as your peridot birthstone is vulnerable to thermal shock. It is safest to use a soft-bristle brush with a mild dish soap in warm water. Peridot should be stored with care to avoid scratching by gems with greater hardness.
We must confess that this August gemstone was definitively not in our radar. However, we managed to dig up some information and a trend of mistaken identity is starting to become clear. Just as Peridot was often confused with emeralds, Sardonyx was often confused with carnelian; which is why when you google Sardonyx jewellery you get Bulgari’s beautiful carnelian pendant.
The most ancient of the August birthstones, sardonyx is a combination of two types of chalcedony (cryptocrystalline quartz): sard and onyx. In ancient times, sardonyx was a popular stone for Roman seals and signet rings, as hot wax would not stick to it. For millennia, the bands of colour in this August birthstone have made it a popular carving material for cameos and intaglios.
Sardonyx is believed to be one of the stones in the High Priest’s breastplate, as referred to in the Old Testament, and to represent the strength of spiritual life. Roman soldiers wore sardonyx rings with the image of Mars carved on them for protection in battle. Today, this August birthstone is associated with courage, happiness and clear communication, bringing stability to marriage and partnerships.
Sardonyx combines alternating layers of sard and onyx—two types of the layered mineral chalcedony—bands of brownish red to brown to dark orange sard alternate with typically white or black layers of onyx to create a zebra-striped gemstone.
Sardonyx, like onyx, shows layers of parallel bands—instead of the chaotic, curved bands that compose agate, another type of chalcedony.
Sard ranges in color from yellowish-red to reddish-brown, depending on how much iron oxide is present. Sard is easily confused with carnelian, another type of chalcedony that is slightly softer and lighter in colour.
The finest examples of sardonyx, which display sharp contrasts between layers, are found in India. Other sources include Brazil, Germany, Czech Republic, Slovakia, Madagascar, Uruguay, and the United States.
Sardonyx is widely available and relatively inexpensive as gems, beads, and jewellery. It is often carved into cameos, intaglios, and brooches to show the colour contrast between layers.
This August birthstone has many sources. India is notable for producing sardonyx with good contrast between the different coloured layers. Sardonyx is also found in Brazil, Germany, Czechoslovakia, Madagascar, Uruguay and the United States, among other localities.
This August birthstone is 6.5 to 7 on the Mohs scale. As with peridot, care should be taken when wearing it, especially as a ring. Note that sardonyx, like other forms of chalcedony, is commonly dyed. High heat, as in jewellery manufacturing or repair techniques, might affect the colour of dyed sardonyx. Warm soapy water and a soft bristle tooth brush is best to clean this gemstone.
Spinel is the master of disguise as it comes in a splendid array of colours and makes itself pass as rubies, emeralds or sapphires! It has managed to work itself to some of the most famous crowns in the history of monarchy. Let us not say that spinel did not have high aspirations! In Covett we appreciate this way of thinking, be more!
The name “spinel” comes from the Latin word spina, which means thorn, in reference to the shape of spinel crystals. This August birthstone comes in a wealth of colours: intense red, vibrant pink, orange, purple, violet, blue and bluish green.
The spinel is often mistaken for either a ruby or pink sapphire, as it can resemble both. In fact, some of the most famous rubies in history have turned out to be spinel. But its distinguishing features, like its octahedral crystal structure and single refraction, are what sets it apart from other gemstones. Spinel also has a lower Mohs' hardness than ruby and sapphire.
Spinel is 8 on the Mohs scale of hardness, so it is typically a durable gem for rings and other jewellery. Ultrasonic and steam cleaners can be used; however, the presence of fractures could pose a problem. Warm soapy water is always a safe alternative.
Red spinel, along with other red gems, was thought to be a remedy for all types of blood loss and inflammatory diseases. The red gems were believed to ease anger and promote harmony. This August birthstone is traditionally given as a 22nd wedding anniversary gift.
Spinel is stable when exposed to light and chemicals. High heat can cause some colours of this August birthstone to fade.
Vivid red is the most desirable colour of spinel gemstones, followed by cobalt blue, bright pink, and bright orange. The more affordable gemstones are often those with paler colours, like lavender. You may also find spinel in black, violet blue, greenish blue, greyish, pale pink, mauve, yellow, or brown.
When shopping for spinel, a high-quality gemstone should have no visible inclusions. The more inclusions, the less valuable the gemstone. Spinel birthstones can be found in various cuts such as octagons, trillions, squares, rounds, ovals, pears, and cushions.
Five world-famous spinels: the stones giving rubies a run for their money
- The Hope Spinel,
- The Black Prince Ruby,
- The Timur Ruby,
- Catherine the Great Spinel, the Imperial Crown
- The Austrian Imperial Crown Spinel
- By the way, the 50.13-carat Hope Spinel fetched $1.47 million at the auction, easily shattering its high estimate of $310,000. The gem set a world record for achieving a price of $30,000 per carat, nearly double the previous record.
For centuries, spinel was mistaken for other gemstones. Some of history’s most famous “rubies” have actually turned out to be this August birthstone.
The approximately 170 ct Black Prince’s “ruby”, for example, was owned by a succession of Moorish and Spanish kings before Edward, Prince of Wales (also known as the Black Prince) received the stone in 1367 as payment for winning a battle on behalf of Peter of Castile. Not until the 18th century was spinel clearly separated from ruby on the basis of their chemical differences. Today, this historic red spinel is set in Great Britain’s Imperial State Crown, just above the 317.40 ct Cullinan II diamond.
Crown of Catherine the Great: The Great Imperial Crown was made for Empress Catherine II the Great's Coronation in 1762. The large red stone at the crest of the crown is the second-largest known spinel, weighing 398 carats. It has been titled: "Catherine the Great's Ruby."
The 170 ct red spinel in the Imperial State Crown is set with more than 3,000 diamonds, sapphires, emeralds and pearls, including the fabulous Cullinan II diamond. It can now be seen in the Tower of London.