Kambaba Jasper | Stone from Madagascar

 

 

kambaba jasper polished pebble

 

Kambaba Jasper Properties and Meaning


Kambaba jasper also known as crocodile jasper is a relatively rare stone which can only be found in Madagascar.  Although often referred to as a mineral it's actually a rock because like all varieties of jasper it's not made up of one single mineral but of many and usually includes other substances as well.

I was first introduced to kambaba jasper in India many years ago whilst choosing cabochons for our collection of gemstone pendants and was told the stone was called star galaxy jasper.  I soon discovered that was a trade name used by gem cutters in Jaipur and that it was actually called kambaba or crocodile jasper.  The name green stromatolite jasper is also sometimes used and having Googled stromatolite I learnt this was a rock-like structure that forms in shallow waters from the build up of a group of bacteria called cyanobacteria.  Also known as blue-green algae, cyanobacteria have a fossil record which dates back almost three and a half billion years so for this reason kambaba jasper is often reported as being more than three billion years old.

 

 

kambaba jasper pendantsKambaba Jasper Pendants from our Collection

 

 

 

Having researched and written about rocks and minerals for many years I'm well aware not everything you read online is factual or accurate and furthermore, there's also a massive problem with plagiarism.  For this reason we always try to check and double check facts before including them in articles that we write and by doing this we have managed to eliminate a great deal of inaccurate information that has been written about this stone.  Many articles that are widely available to read online have repeatedly been plagiarised and each time the information is rewritten, more facts about the geological makeup of kambaba jasper are excluded or misunderstood.  For this reason much of what you read about it is no longer accurate.  After some digging I found an interesting forum thread which although quite old, talks about the stone in great detail.  It was started by someone who asked whether it was a stromatolite and the replies which cover several pages feature arguments both for and against. Having read it carefully I found the following comment particularly interesting:

I’ve been sitting on my hands trying to stay out of this debate. There's a lot of hokum and claptrap kicking around concerning this material which has created considerable confusion. “Kambaba Jasper” is an invented name for what was hailed in the fringes of the lapidary world as a new material but it isn’t, it's a relatively newly-discovered exposure of an already known material. It has been studied by experts and isn’t stromatolitic or even sedimentary at least not in the samples that have been analysed.

The EPI (Institut für Edelstein Prufüng) or Institute for Gemstone Testing in Germany published a detailed report in one of its bulletins but unfortunately they're only available to members and are only published in German. Nevertheless paraphrasing a bit from their findings, thin-section and X-Ray diffraction analyses have shown that the kabamba material is not a type of jasper at all, it’s volcanic, the green groundmass is composed mainly of quartz, pyroxene (aegirine) with orbicles of alkali feldspar embedded with streaky aggregates comprising tiny needles of amphibole (riebeckite to pargasite). The formation is not fully understood but is most likely to be a volcanic rock that has been “overprinted” by a weak metamorphism. In mineral composition it’s very similar to a rock originating in Mexico that’s generally referred to in the lapidary world as “Eldarite” although the colouration is the reverse of the Madagascan material. Eldarite has a dark groundmass and pale orbical patterns and Kabamba Jasper has a pale groundmass and dark orbicles. Eldarite is also known in America as “Nebula Stone” since after being polished, the patterns resemble nebulae in outer space. The two rocks are nevertheless sufficiently similar from a mineralogical perspective that the EPI recommends the names “Eldarite” and “Kambaba” (with its several spelling variations) should be regarded as synonyms. They also advise that the name “Kabamba Jasper” should be replaced by "Kabamba Stone." (this is the original thread)


slab of kambaba jasper rockPhoto Courtesy of Marco Campos-Venuti

 

The thread had been closed for some time so I asked in a different forum relating to rocks and minerals whether anyone could shed any light on exactly what type of rock this was.  One response I received was from a mineralogist who told me he had spent time working in Madagascar and went on to explain the confusion over whether kambaba jasper was a stromatolite or not stems from the fact that two totally different stones with very similar names have over time become mixed up. Kambaba jasper or kabamba jasper as it's also known, comes from a small area in Madagascar known as Kabamba which lies in the west central Bongolava region and the name Kabamba is sometimes also written as Kambaba. This type of rock is an oncolite stromatolite which is a rock-like structure that forms in shallow seas and is built up from bacteria which has over time, been replaced by silica. The other stone known as Kambaby Ocean Jasper is a variety of orbicular jasper so is formed in a totally different way and is neither a stromatolite or even a sedimentary rock and it's very possible this is the material that was examined by the Institute of Gemstone Testing in Germany.

If correct, it's completely understandable why information about the two stones has become mixed up and with the continuous plagiarism and paraphrasing of articles, it has led to a great deal of confusion and inaccuracy.  Photos of the different rocks plus additional information can be found in this article (you'll need to scroll down to see the thread). 

The stone that we have always known as kambaba jasper or crocodile jasper has distinctive green and black colouration and is used mostly for lapidary purposes.  Until fairly recently we were unaware of the existence of the variety of ocean jasper known as kambaby ocean jasper.

Kambaba jasper grades 6½ to 7 on Mohs scale of mineral hardness and like so many plant and animal species in Madagascar, it cannot be found anywhere else in the world.

 

 

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