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 Post subject: My finding: Sarawak amber from various geological formations
PostPosted: Wed Dec 30, 2015 12:26 pm 
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Hi,
Here is the amber I found recently in Mukah roadcut area, Sarawak, Malaysia. Liang formation, Plio-Pleistocene age. The amber situated in ~2 million years old strata. Which is extremely young for normal amber. They pass the acetone test and crazing free.


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File comment: Transparent reddish Liang formation amber
lianng.jpg
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File comment: Liang formation amber
mbeee.jpg
mbeee.jpg [ 20.63 KiB | Viewed 1821 times ]
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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 12:42 pm 
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Liang formation, Mukah-Selangau road, Sarawak, Malaysia


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File comment: Amber bearing strata
liangsss.jpg
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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 12:51 pm 
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That's really interesting. I had thought that Sarawak amber was found in veins in coal seams, but it looks like you're pulling it out of shale. I wonder if it's a secondary deposit, chunks that floated away and were (somehow) mixed in with deposited sediments.

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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 1:03 pm 
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Perhaps they redeposited at shallow marine shale during Early Pleistocene high sea level. Original source of these amber came from Plio-Pleistocene thick lignite seam at that area too. So, I can only assumed that amber 2-3 million years old.


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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 1:11 pm 
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Begrih formation, slightly older, Lower Pliocene about 4 million years old...these amber came directly from lignite seams. Most are very brittle but a few of them can be cut as organic gems. :)


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File comment: Begrih formation White amber
beggg.jpg
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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 4:24 pm 
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Location: Wylie Texas but in Alaska for a while
some beautiful amber. Thanks for sharing


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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 4:36 pm 
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As a side-note, this stuff hit Tucson pretty hard last year, and I picked up a few pounds of smaller pieces from a friend of mine. A lot of it was being sold as Indonesian but one of the dealers said it was actually Malaysian. I've had pretty good luck with the pieces I've worked with, though I suspect your pieces are probably of higher quality since they've already proved they can survive under difficult conditions. Anyway, it's really beautiful stuff. No bugs in any I've looked at so far but hope springs eternal.

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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Wed Dec 30, 2015 9:28 pm 
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Mine have bugs in it


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File comment: Plio-Pleistocene age ant inside amber
liang resample.jpg
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File comment: Plio-Pleistocene age insect inside amber
lianng dd.jpg
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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Fri Jan 01, 2016 1:12 pm 
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Opaque black amber.. remind me pseudostantienite.


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File comment: Pure Black amber from Begrih formation.
for gemm.jpg
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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Fri Jan 01, 2016 1:22 pm 
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Balingian formation, Late Miocene, ~9 million years old lignite seams. The first ever blue Malaysian amber.


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File comment: Transparent Blue Balingian formation amber
luuu.jpg
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File comment: Blue Balingian formation amber.
12049522_10204058913991825_6692215594288582334_n.jpg
12049522_10204058913991825_6692215594288582334_n.jpg [ 38.99 KiB | Viewed 1777 times ]
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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Fri Jan 01, 2016 3:33 pm 
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A few articles of Blue and Related Amber:

-Indonesian Blue Amber from the Island of Sumatra*


-Is amber from Indonesia a gem amber or just fossil resin??

-Color Phenomena of Blue Amber

*Personal Note, I don't agree with the definition of the Usambara effect described within the article above. A better explanation is here: The Usambara Effect An Overview of its Nature, Skalwold


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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Sat Jan 02, 2016 4:21 am 
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Usambara effect usually occurs in crystalline gems like some tourmaline etc. Depends on the light path through the material. I don't know if amorphous material do have usambara effect too...


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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Sat Jan 02, 2016 12:03 pm 
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There seem to be some who have documented usambara in amber. I am not one of them.
But I believe that this phenomena was originally called "color shift" in an article discussing garnets.
I know one of us will find a link for you.


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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Sat Jan 02, 2016 4:08 pm 
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Iskandarman wrote:
Usambara effect usually occurs in crystalline gems like some tourmaline etc. Depends on the light path through the material. I don't know if amorphous material do have usambara effect too...

You can observe the same light-path-dependent color effect in non-crystalline material.


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 Post subject: Re: My finding: Sarawak amber from various geological format
PostPosted: Sat Jan 02, 2016 4:34 pm 
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I feel like practically every transparent orange-red material is going to look yellow or amber when cut thin. It's such a ubiquitous phenomenon it seems strange for them to even comment on it--no doubt it has origins similar to a proper usumbara with regards to relative perception of red and yellow color components at different levels, but unlike a red/green change it's not unfamiliar or particularly interesting.

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