Joined: Sat Jul 07, 2007 8:06 am Posts: 418 Location: uk
Hi Yeti the amber looks good , how was it to work with the blue ,is it stable? it seems its not highly oxidized then like alot of red amber, that is likely to fracture break or even crumbie. I have not worked with blue amber. Back in the late 1990s someone had a few kilos It was in Simojovel. I did not buy thinking maybe the fluorescence blue was just on the surface, and would be lost in the sanding
Joined: Sun Mar 13, 2011 10:36 am Posts: 35 Location: Canada
Dave, the Indonesian amber seems to be more copal than amber, it gums up when cutting, prone to breaking and doesn't polish as nicely as chiapas or baltic. The colour varies widely from a murky chocolate to a cloudy clear and is consistent under the surface making it quite difficult to search for inclusions.
JMHO, i'm still a nubie when it comes to this stuff.
Joined: Sun Mar 13, 2011 10:36 am Posts: 35 Location: Canada
Having said all that (my rant for the week) i have another installment of "Fun with Light" for your perusal and edification...pic 1 shows natural light with a black background. pic 2 shows natural light with a white background. pic 3 shown with white led backlight illustrating the red inclusion flow interspersed with the clearer amber.
So what is it...red, white, or blue amber? Your call.
This indonesian amber is from the Kalimantan coal fields.
Regards Yeti
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Joined: Sat Jul 07, 2007 8:06 am Posts: 418 Location: uk
Hi Yeti Lots of fluorescence colores in your amber Not much information to be found on indonesion amber On the web no scientific papers at all on it. Sue Aber Ward as the resin coming from a tree in the family Dipterocarpaceae. the same family of tree which as produced the new found amber deposits in Gujarat India Its interesting that this family of tree is still dominant in north Borneo Do not know how much of this amber from Gujarat is gem quality Though it is said to be about 50 million year old, alot of it is not fully fossilized & still is copal or in a state between amber & copal Yeti You found any interesting inclusion in the Indonesion amber
Joined: Wed Jan 23, 2013 5:29 pm Posts: 1047 Location: Paris
I have found 2 weeks ago in Sainte-Marie aux Mines a piece (55 carats) of blue amber from Kalimantan which left me jaw-dropping. The deep blue fluorescence is really impressive and much stronger than any of the blue domenican amber which I have seen so far (and I have seen and brought back from there really nice samples). You don't need any particular lighting to get the blue effect, even under dim sunshine the piece looks very blue. Under LED lights it is just uniform navy blue. Beautiful... and cheap.
The piece is just polished, translucent but rather cloudy, as Yeti says, and the polish is not so good, with a sticky feeling under the fingers. I'll try to see if I can improve the polish.
I haven't tested it yet with acetone or alcohol. I understand that the Kalimantan blue amber (or copal) is a recent find, is it why you cannot find much information about it ?
Joined: Sat Jul 07, 2007 8:06 am Posts: 418 Location: uk
Hi Isi How did You get on polishing the amber In Mexico after fine sanding with a well worn 1200 or 1600 grit sanding paper hand polishing it is on polystyrene using brasso metal polish, it works well lot of interest from scientists in the inclusion in the amber from Gujarat India as it comes from a time 50 million years ago when India was still not connected to Asia Strange can not find any information on the inclusions in amber from Indonesia
Joined: Wed Jan 23, 2013 5:29 pm Posts: 1047 Location: Paris
As for the polishing I'll keep you updated within a few days. I don't have the necessary tools myself, I'll just bring the piece to a good friend of mine, lapidary, who has all sorts of grinding wheels... But is currently on holiday.
I've tested the piece with acetone and alcohol. Both solvents left the surface absolutely undamaged. The luster seems to be even improved ; probably it had a cleansing effect.
There is a strange inclusion inside, like a kind of big leaf curled upon itself, with much oxidation ; hard to describe. Otherwise the stuff is clear, brownish yellow in transmitted light.
Joined: Sun Mar 13, 2011 10:36 am Posts: 35 Location: Canada
Welcome to the chat Isi...the blue is indeed a very rich colour, quite different.
you said..."probably it had a cleansing effect"
Heres my theory on that, i think the original resin is a very clear substance similar to chiapas based on some chips i broke off and anything else in the above samples are possible inclusions (by definition) of a swampwater mix that occurred as the resin settled in the prehistoric peat bog/swamp that eons later became the Kalimantan coalfield. (just guessing at this.)
That might explain the reddish inclusive (white LED) flow throughout some samples and also possibly explain the surface texture that is very slightly tacky, it also could explain the gumming up under a tool unless worked at much lower speeds than Chiapas or Baltic. I think the actual resin has turned to amber alright and when cleaned with acetone, any surface oily bits are dissolved, leaving a fresh glossy surface.
What i don't quite get is a few days later i go back and recheck the sample, it's not quite as glossy (to the touch) anymore... its almost as if the minescule oily bits have migrated to the surface again...i guess a microscope and a chemical analysis of the specific red pigments may help with this.
Joined: Wed Jan 23, 2013 5:29 pm Posts: 1047 Location: Paris
Very interesting, Yeti.
Actually under the binocular I could see the small reddish dots you talk about, surrounding the oxidised included area.
I look forward to having my piece neatly repolished, so that I can check afterwards if the sticky feeling comes back.
I find it a pity that the material is turbid in look and that the high polish cannot be retained ; otherwise, with its amazing blue fluorescence, this amber might become a big sensation among organic gems !
Joined: Wed Jan 23, 2013 5:29 pm Posts: 1047 Location: Paris
I eventually had my blue amber repolished. The surface is really improved but still it seems impossible to get rid of the slightly sticky, elastic touch. I could not obtain a glossy, shiny polish like that of other types of amber (baltic, burmese, mexican, domenican).
Joined: Wed Jan 23, 2013 5:29 pm Posts: 1047 Location: Paris
Hi all, I confirm Yeti's observation : a few days after repolishing, the surface of my indonesian blue amber seems again to be sticky and slightly greasy as before. As if some fluids from inside had seeped through anew. Very odd indeed !
"Dave, the Indonesian amber seems to be more copal than amber, it gums up when cutting, prone to breaking and doesn't polish as nicely as chiapas or baltic. The colour varies widely from a murky chocolate to a cloudy clear and is consistent under the surface making it quite difficult to search for inclusions. JMHO, i'm still a nubie when it comes to this stuff. Yeti"
Hi Yeti, You are probably right, Indonesian amber it's definetely more copal than amber, besides guming and not polishing well,it's waxy in appearance and oxidises very quickly, loosing its blue hues,the blues and greens fluorescence in copal and amber do not disappear when sanding, it's rather the oxidation that inhibits the fluorescence, when polishing again, the amber and copals will show the blues or greens again.
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