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Author Topic: Marra Mumba Tiger Eye  (Read 132 times)

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Opal Mike

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Marra Mumba Tiger Eye
« on: March 26, 2020, 11:18:50 PM »

Hi all,

Since I stopped commercial wholesale production in my opal workshops, I have had a lot of fun sourcing and cutting some different material, mostly Australian rough.

I have always loved Marra Mumba Tiger eye and I have been playing with it for a while now.

I noticed a post that talked about asbestos risk in tiger eye and I thought I would add to it. Firstly I think most of you know that tiger eye is formed by a process that sees the original asbestos fibres replaced by quartz type columns or fine fibres. Most definitions will state that the new ‘tiger eye’ as replacing the older asbestos, is now free of asbestos and safe to cut for us lapidaries.

Felecia is spot on though with her comments, and this is pertaining to the highly sought after Australian Marra Mumba variety. This material varies greatly in hardness, with some material, especially the blue stuff often being more fibrous, and yes clearly containing silky unstable threads of asbestos. It doesn’t end there though. You can find this in the bronze redder material synonymous with Marra Mumba, and indeed some of the yellow and golden coloured material.

Care needs to be taken!

Whilst the majority of this majestic stone is pretty safe to work I would urge all of you to presume the following; it isn’t!

You can work this stuff safely. Make sure you take the steps Felicia adopts by making sure you never grind or sand this material dry...use plenty of water. I would expressly add the following to that; wear a mask at all times, and when you have done with the grinder and sanding stages on your wheels, make sure to clean everything properly and safely. Scrape and bag up the wet sludge residue as built up on and around the machines and trays every day; don’t let the ground residue build up and dry out and potentially tun into breathable dust particles.

I keep my workshops very clean. I mop the floor every day, clean the machines and keep all dust to a minimum....we can all do that whatever our space, and whatever machines we use.

For anyone that thinks asbestos is nothing to worry about, think again. No stone dust is good for us, silicates etc, so get used to keeping things clean, and wear masks all the time.

For those that don’t know what Marra Mumba tiger eye is please keep reading.

The Murra Mumba brand was first established in Western Australia following a deposit of stunning tiger eye found in the 1970’s by Glenn Archer. This material contained the red bronze tiger eye and was mixed with bands of hematite and a variety of stunning jaspers. By definition, Marra Mumba must contain a mix of these colour especially the bronze tiger eye, along with the Jaspers and hematite. The material is simply stunning with amazing chatoyant vibrant colours and patterns, and very different from the more abundant golden banded varieties coming out of Africa.

Tiger eye is notoriously challenging to cut in terms of achieving a nice glossy fine polish, and each stone varies in that regard.

There has only been two deposits of this found with Glenn finding the second deposit several hundred metres away from the first on the same ridge in 1994.

Unfortunately this is the only ridge in the world that produces this amazing material and is is now gone, swallowed up by a massive iron ore mine that just rips through everything to get to the iron ore.

I will post some pics on some pieces that I have on the go at the moment. You can see the hematite bands and if you look closely a couple of clear quartz bands and some nice jasper, which is typical of the better Marra Mumba.

Mike
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peruano

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Re: Marra Mumba Tiger Eye
« Reply #1 on: March 27, 2020, 05:52:35 AM »

Thanks for your experiences and comments. Caution without the alarmism that if too often projected when risks are pointed out.  Shop cleanup and machine cleanout are too often ignored because their health benefits are not appreciated.  Thanks again for cogent explanation. 
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Combining a love of bikes (pedal and otherwise) with hiking, hounding, lapidary, and the great outdoors

ileney

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Re: Marra Mumba Tiger Eye
« Reply #2 on: March 30, 2020, 07:04:15 PM »

Thank you so much for your thoughts on this as it had been a worry of mine. I appreciate the reminder about precautions.
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Opal Mike

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Re: Marra Mumba Tiger Eye
« Reply #3 on: March 31, 2020, 06:03:34 PM »

I have just finished shaping some beautiful old Marra Mumba rough...classic Marra Mumba material, with the original Marra Mumba palette of colours and patterns which makes it so rare and desirable.

I love my opal, but this stuff is right up there!

Enjoy,
Mike
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irockhound

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Re: Marra Mumba Tiger Eye
« Reply #4 on: March 31, 2020, 06:20:20 PM »

I cut these for an acquaintance some time back.  I loved the subtle color changes in the material.  I had bought some rough but it never turned out like these.
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Opal Mike

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Re: Marra Mumba Tiger Eye
« Reply #5 on: March 31, 2020, 06:53:06 PM »

Nice!  No doubt some pieces cut better than others. The material varies a fair bit and some is pretty hard to get a nice polish, but it is rewarding when the planets align.

I like your shapes! 👍👍
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Felicia

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Re: Marra Mumba Tiger Eye
« Reply #6 on: March 31, 2020, 08:50:37 PM »

Just great. The colors and the shapes
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vitzitziltecpatl

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Re: Marra Mumba Tiger Eye
« Reply #7 on: Today at 06:29:46 AM »

Great photos and, once again, invaluable info.

It's so good of you to post photos of the "real" thing. So many things in the lapidary world get mis-identified, and over time people become convinced that what they've always heard or read just has to be correct.

We appreciate the education.
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