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Coralline Triangle – Pun Intended!

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9 March 2010

Sometime August last year, during our trip on the Seven Seas diving around Komodo National Park, we met Jack Shargel, an animated American jeweler based in Bali.  Jack, upon hearing what it was we were doing, showed us a somewhat different coral triangle!  He opened his magic jewel pouch and brought out beautiful looking gems that we knew we had to photograph – fossilized corals mined from the mountains of Sumatra shaped into triangles!


This story for us goes a few years back from an anecdote told to Yogi by a prominent Australian coral scientist who once attended an international Coral Triangle Initiative workshop full of scientists, regional representatives from NGOs and government. After the workshop, he was approached by an delegate and was asked “I’ve never seen a coral triangle before. Can you show me one?” Hmmmmm, they didn’t quite get it . . .

Well, what I’m showing here in this entry is not quite what we’ve been showing as THE Coral Triangle – the marine eco-region that we’ve been photographically portraying by land, sea and air for close to a year now. Lest I confuse you, here is the map of the Coral Triangle Region that we’re putting a face to through our images and stories.


And now here is the interesting twist. This may be what the prominent Australian coral scientist may jokingly want to show the confused delegate. Below are petrified or fossilized corals from the miocene period that dates back approximately 20 million years ago. To ride with the CT bandwagon, our friend Jack has had them shaped into triangles and markets it as coralline triangles!


Most of the mined corals are like the ones shown above with an opaque feel to it. But what sort made us oooh and aaaah are the translucent ones where light could shine through and show the beautiful flower like coral polyps. Feast your eyes out on these rare gems!




The volcanic islands of Indonesia are host to numerous deposits of fossil coral. The Barisan Mountain Range, along the western boundary of the Island of Sumatra, hosts a rare and ornate suite of fossils. Miocene age (approx 20 million year old) coralline reefs and near shore forests were preserved by burial in volcanic sediments rich in minerals including iron, manganese and silica. Thru a combination of processes the full pattern and character of the original coral life forms have been preserved in great detail.


“Permineralization” is the process of filling pore space in and around the remnant hard coral skeleton with minerals deposited from solutions trapped or migrating thru the sedimentary pile as it is compressed into rock. “Replacement” happens when the original coral skeleton is replaced molecule by molecule with a mineral or minerals from a solution. For example, calcium carbonate (CaCO3) from the hard structure of the coral is replaced by silica (SiO2) from trapped or migrating solutions as rock was being formed.


Jack has designed a new interesting series and hands over the gems to the deft hands of Balinese goldsmiths or craftsmen. Jack has turned these gems into jewelry. Interested? You can contact Jack Shargel at tarakhkg@indosat.net.id

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