Professional Jeweler Archive: The Sea's Vanishing Gift

August 2003

Gemstones & Pearls/News


The Sea's Vanishing Gift

Natural pink and red coral sizzles as a fashion item, but the gem is becoming more rare


Go ahead and label reddish gem coral indispensable. Why not? It performs in full glory as magnificent carvings, beads and couture jewelry, while also adorning inexpensive baubles at department stores. But as demand grows among consumers of all ages, so does the need to understand coral’s finite resources.

Coral is organic, made up of millions of exoskeletons of tiny marine animal polyps built up in tree-like colonies. Gem coral grows – remarkably slowly – in warmer ocean waters, most often between the Tropic of Cancer and the Tropic of Capricorn. Famous localities include Mediterranean sites, the Sea of Japan and Australia’s Great Barrier Reef. Italy is the present-day coral cultural, design and production center.

Large quantities of coral are bleached, dyed or stabilized with epoxy resin (or a combination) for use in jewelry. But because of the growing concern over the decimation of coral reefs, this gem’s days might be numbered.

Ocean Beauty

Calcareous (calcium-based) coral’s attraction is the assortment of red, russet, salmon and delicate pinkish-white shades – the so-called precious corals. Others, such as rare blue varieties, are seldom seen in jewelry, except for black and golden coral made of the organic protein conchiolin and sold to tourists in the Caribbean and Hawaii. But when it comes to precious coral, the genus corallium rubrum (pink to red) rules the roost for several reasons:

  • Versatility yields beads, pendants, pins, rings and earrings, carved or cabochon.
  • The warm hues are easily matched with cool blues, such as turquoise.
  • Diamond accents lift coral into the high-end.
  • It’s compatible with any precious metal.

History Class

In its Middle Ages heyday, Mediterranean coral was used in religious beads and small carvings and cameos. It was traded along ancient silk routes between Europe and Egypt and China as early as 100 B.C., says The History of Beads by Lois Sherr Dubin (Harry N. Abrams, 1987). Traders offered coral in exchange for silk, spices, porcelain and lacquer in the Far East and for many products from Africa.

Over time, enthusiasts came to believe coral would guard wearers from poison, enchantment or spells, along with ulcers, kidney stones and general misfortune. Once coral is broken, according to ancient belief, those protective powers ooze out.

Endangered Coral

Well over half of the coral reefs worldwide are at risk, and many of them are legally protected. Several genera and species have been added to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), though most listed now aren’t used in jewelry. Why the concern? Coral reefs are habitats for many species of fish and other wildlife. They also provide shoreline protection against erosion and act as ocean filters. Ongoing decimation has already had negative impacts on many marine environments and sealife.

“The corallium precious corals are not on the CITES list for now, but they are in trouble because harvesting of this material is not being actively managed,” says Dr. A. Bruckner, a coral reef ecologist with the National Oceanic and Atmospheric Administration who is working to get pink coral on the CITES list. “You just don’t see any of the big, old colonies of pink coral – it’s getting thinner and thinner.”

Jewelry coral expert Roben Hogobian of R.H. & Co., Glendale, CA, confirms coral is harder to find in shallower areas of the Mediterranean. “Divers have to go a lot deeper than they did just six years ago,” he says.

Treatments

More affordable forms of coral are widespread in the jewelry market, but they generally are subject to treatment such as:

  • Bleaching, which achieves uniformity in coral with mottled coloration.
  • Dyeing deep red “oxblood” or light pink “angelskin.” Some is bleached first.
  • Impregnation with epoxy resin. The growth structures are easily visible.
  • Reconstitution of poor-quality coral that’s ground into a powder then mixed with a binding agent such as epoxy resin to form blocks that can be formed for use in jewelry. Such material should not be called coral. Coral’s fibrous, layered structure and tree-ring structures are not apparent in this material.

The Imitators

For customers who can’t afford or don’t want coral, there are substitutes. One is a Gilson imitation in red and pink. It’s semitranslucent to opaque like coral, but it exhibits a granular structure rather than the wavy fibrous characteristic of natural coral. Dyed chalcedony and glass can be distinguished from coral because of the lack of structure, appearance and specific gravity.

• RH & Co., Glendale, CA; (800) 242-1233.

• Behnam Jewelry Corp., New York City; (212) 302-7800.

– by Robert Weldon, G.G.

All photos by Robert Weldon.

From left, “oxblood” red coral beads are 12.5-17mm and up, pink-orange button cabochons weigh a total of 125.84 carats, the red pear-shaped coral is 81.87 carats and the salmon-orange coral beads range from 17mm to 24mm. Gems are courtesy of R.H. & Co., Glendale, CA.
Silver bracelet, earrings and ring with color-enhanced red coral are from the Frederica Collection by Behnam Jewelry Corp., New York City.
This 2-in. long salmon-pink coral was carved in Italy. Gem courtesy of R.H. & Co., Glendale, CA.

The photo at left shows inexpensive, brittle branch coral before epoxy impregnation. The photo right shows coral after impregnation and ready to be fashioned into cabochons. Courtesy of Colbaugh Processing, Kingman, AZ.

Copyright © 2003 by Bond Communications