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Articles from GEMSTONES - CORAL / MOTHER OF PEARL (2 Articles)











Organic Gems Part VI: Coral

Coral has a long history of use in jewellery. Many cultures across the world have valued coral for adornment, and also for its reputed mystical features. As well as being prized for jewellery, red coral was valued as a charm to ward off evil and to increase fertility. It was held to protect against snakebite and reduce fevers.

Warriors in central Europe adorned their shields and helmets with coral to protect them in battle. Throughout medieval Europe, coral was worn as a protective charm. In Italy and Spain today, coral remains treasured for its protective properties.

Known by a range of names including red coral, deep-sea coral, and precious coral, Corallium rubrum is the skeleton of communities of marine creatures called polyps. Comprised of calcium carbonate, unpolished coral has a matte appearance with a dimpled surface. A relatively soft gem (3.5 on the Mohs scale), coral is typically fashioned into beads and cabochons.

The red coral used in jewellery comes from the Mediterranean Sea and the depths of the Atlantic and western Pacific Oceans. It is distinguished from reef building coral, which grows in relatively shallow seas, by its colour and growth habits. Relying on deep waters and currents to thrive, red coral grows very slowly – approximately a millimetre per year – with its million of polyps sifting the currents for nutrients. Unlike reef coral, red coral has a shrub-like form.

"Relying on deep waters and currents to thrive, red coral grows very slowly approximately a millimetre per year with its million of polyps sifting the currents for nutrients"

In the ancient world, the primary source of red coral was the Mediterranean Sea. Coral was traded widely between civilisations around the region and as far away as India, where it was believed to have mystical and medicinal properties.

The word coral denotes the colour red, however coral comes in a range of colours including pink, blue, black and gold. It is the deep red colour that has been prized for thousands of years. Sought for its rich hue and glass-like shine when polished, coral has been used in decorative items and as adornment for millennia.

During the Victorian era (1837-1901) coral was a popular gem, with jewellers fashioning flowers, butterflies and cameos. In the early decades of the 20th century, coral remained popular, adding a vibrant splash of colour to all manner of jewellery and hair ornaments.

Over-harvesting across the world has depleted natural sources of many varieties of coral, including red coral. A number of countries, including Australia, restrict the importation and sale of various species of coral for this reason.

Consequently, much of the coral seen today in newer jewellery is not natural red coral, but dyed bamboo coral, a more widely available material. More porous than red coral and lacking the rich red colour, bamboo coral is hardened by filling with resin. It is then dyed red in imitation of red coral and polished.

A porous material, coral absorbs lotions and make-up when it is worn against the skin. Over time, exposure to chemicals and perfumes may damage the gem’s relatively soft surface.

To clean it, wipe with a soft damp cloth. Coral should never be soaked in a cleaning solution or placed in an ultrasonic cleaner. It should also be stored away from other jewellery that may scratch the coral’s surface.











ABOUT THE AUTHOR
Susan Hartwig

Susan Hartwig FGAA came late to the world of gemmology after a long career in corporate training and project management. She combines her love for writing with a passion for gems and jewellery. Susan writes regularly for her gemmology blog ellysiagems.com. For more information on gemmology courses and gemstones, visit: gem.org.au

Bharat Diamond Bourse
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Friday, 20 September, 2019 09:38pm
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