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Post by christopherl1234 on Dec 6, 2012 15:03:50 GMT -5
Finished this one up last night for a custom order. What do you all think?? 35mm round 7mm thick It was a little tricky trying to capture all the chatoyancy in this cab so I included two photos Christopher
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Post by rockjunquie on Dec 6, 2012 15:06:50 GMT -5
I think you did a fine job.
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Post by FrogAndBearCreations on Dec 6, 2012 19:11:55 GMT -5
Pretty cool!
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Post by krazydiamond on Dec 6, 2012 21:36:00 GMT -5
sweet.
KD
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RocknCritter
spending too much on rocks
Member since November 2008
Posts: 489
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Post by RocknCritter on Dec 6, 2012 21:58:25 GMT -5
That's a nice cab from beautiful material! You did a great job with the round shape.
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Post by Bikerrandy on Dec 6, 2012 22:03:06 GMT -5
Nice! Looks like a planet
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pporky
fully equipped rock polisher
Member since May 2007
Posts: 1,932
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Post by pporky on Dec 7, 2012 15:55:34 GMT -5
Nice one
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hubrocks
fully equipped rock polisher
Member since April 2011
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Post by hubrocks on Dec 8, 2012 0:59:24 GMT -5
;D Yes Randy looks like Jupiter! Daz a cool cab Christopher!!!............Hub
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Post by talkingstones on Dec 8, 2012 17:28:23 GMT -5
I like the wood grain look to it!!!!
Cathy
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darrad
fully equipped rock polisher
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Post by darrad on Dec 8, 2012 19:51:01 GMT -5
Nice! Good job catching the chatoyancy in the photo.
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bushkraft
having dreams about rocks
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Post by bushkraft on Dec 9, 2012 7:46:46 GMT -5
Sorry my friend but that is not marra mamba, what you have there is a piece of Brockman tiger eye, still beautiful in its own right but nothing like the true marra mamba material which was formed millions of years before and consequently lies much deeper than the Brockman material.
The marra mamba material is currently found only in one small valley where the marra mamba iron formation has been pushed up and through the over lying Brockman formation.
In case you are wondering how I know this ... a friend of mine owns the deposit.
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SteveHolmes
fully equipped rock polisher
Member since July 2009
Posts: 1,900
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Post by SteveHolmes on Dec 9, 2012 11:27:22 GMT -5
Beautiful Cab Chirs! I have a couple of big slabs of Marra Mamba that I've just been waiting to cab for the right time. Interesting bushkraft. I bet it's fun having a friend own such a deposit. Maybe he could give us RTH'ers a deal on some rough. Whattya think? steve
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bushkraft
having dreams about rocks
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Post by bushkraft on Dec 9, 2012 17:17:31 GMT -5
Hi Steve, He will be at the Tucson show, a container load of Western Australian material left here a few days ago, with some absolutely stunning marra mamba specimens and slabs among the load .... ask for Richard and tell him "Pete sent ya" !!
I spend most of my day cabbing marra mamba and tiger iron, I have been doing it for 25 years and am still fascinated by the material, a few recent pieces have produced multi coloured spots rather than the usual stripes, they are simply gorgeous and look a bit like the test sheets for colour blindness but highly chatoyant .... will add a photo when the sun comes up.
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bushkraft
having dreams about rocks
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Post by bushkraft on Dec 9, 2012 19:13:54 GMT -5
Latest colour variation discovered in the marra mamba formation.
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Post by christopherl1234 on Dec 9, 2012 21:47:44 GMT -5
I have a few questions.... The cab I cut and the rough it came from has the red and metallic material just as your example slab has and the matrix looks very similar also. My question is how to tell the difference and is it easy to tell from just a photograph Here is another cab I cut from the same material I would have to search my archives to post any other cabs I have cut from this material. Over the years I have cut cabs here and there from the same stock I have had in my inventory for many years. Any help you could provide would be greatly appreciated bushkraft
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Post by Tony W on Dec 9, 2012 22:23:17 GMT -5
Nice work, and interesting discussion! T
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bushkraft
having dreams about rocks
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Post by bushkraft on Dec 9, 2012 23:45:36 GMT -5
Chris, It is all rather complicated but I will give it a go ..... The marra mamba formation is the bottom most formation within a suit of iron formations known as the Hamersley group, above it lies the Brockman formation which also contains crocodolite (which when mixed with enough silica becomes tiger eye, in its raw state without the silica it is better known as blue asbestos) Both these formations form part of the Hamersley group and together along with other groups form what is known as an Iron province, the Western Australian iron province measures about 85,000 sq kms and in places is up to a mile thick .... It is estimated to contain enough iron ore to last the world for 4,000 years at current consumption rates, (The great lakes area is the best known North American iron province). The jasper within the much older marra mamba formation tends to be more colourful than that of the younger Brockman formation and this in turn is responsible for leeching colour into any nearby tiger eye, the Brockman formation contains lots of goethite which is usually yellow, whereas the marra mamba formation contains more haematite (plus other minerals)which stains things red or orange, the natural colour of the crocidolite is either silvery grey or blue so when mixed with other colours it becomes green red orange dark blue or occasionally a very attractive port wine colour or any mixes of the above. It is possible to determine which formation a sample of tiger eye or the surrounding jasper matrix comes from, but just to confuse things in some areas a large amount of folding has taken place pushing the marra mamba formation up through the overlying formations and close to the surface, it is in these areas that we explore for the coveted marra mamba tiger eye, (most of which is to soft too work with without stabilisation) because we get to find it we also get to name it and generally speaking if it contains colours other than gold we refer to it as marra mamba if it is just gold then it is referred to as simply Brockman tiger eye which is far more common than the multi coloured marra mamba material.
Of course when the two formations have been jumbled up it becomes a bit tricky I have seen slabs containing 4 distinct forms of tiger eye all within a few inches of each other. Your jasper cab does look as though it belongs to the marra mamba formation but the tiger eye pictured in your original photo a simply due the lack of colour does not ..... there is far more to this story but I don't have time to relate all that I know right now so it will have wait for a while, but I do hope that this little bit of information has helped.
Take care.
It should be remembered that this process began over 3 billion years ago and continued for another 1.8 billion years, even the experts admit that much of what they tell us is purely well informed speculation.
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Post by christopherl1234 on Dec 11, 2012 0:14:35 GMT -5
Thank you bushkraft for sharing this very interesting and informative response. I love learning. I can see how tricky it can be to classify materials at times. The Jasper cab came from the very same material that the first round cab came from. That cab came from a part of the slab I cut that had very little of the golden asbestos and mostly of the matrix. These following cabs also came from the same material that the round cab came from. piece of the slab the cab I ended up with piece of the slab cab I ended up with both of these cabs came from the same slab just different sides of it. I imagine this may be a good example of how cabs cut from the same material, even the same slabs, can look so different. So would these all be considered Brockman since all of the cabs came from the same material?
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bushkraft
having dreams about rocks
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Post by bushkraft on Dec 12, 2012 8:25:34 GMT -5
Chris, most people in the trade associate the name Marra mamba with boldly coloured tiger eye and a higher than average level of chatoyance, I have sold many gold coloured cabs over the years but do not add the marra mamba prefix as a sales pitch for this material, in this way I hope that we can maintain the added value synonymous with the marra mamba name tag. I have seen slabs and cabs for sale on some of the auction websites where the item for sale is very obviously not marra mamba, one seller offers what he terms as 'South African green marra mamba' which is ridiculous. This is a piece that I completed yesterday and photographed this morning ..... And a few that I am working on today, all came from the same slab .... the cab on the right will not be sold with the marra mamba prefix. This a view of my stall that I set up close to the beach every Saturday I usually sell between 15 and 25 pendants and the odd large slab. And the view from my stall not such a bad place to spend the day!!
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Post by christopherl1234 on Dec 13, 2012 0:47:09 GMT -5
Thank you for taking the time to explain all this to me. So if the material is predominately gold even if it is from Marra Mamba rough than it will be called Brockman and the cabs with more color are Marra Mamba...got it. So Marra Mamba is more a grade name than a type it seems. Thank you sir. I must agree that most definately looks like a swell place to spend the day!!
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