Opal Odyssey - Voyage into Deep Space

[OpalSpectrum]

topic about opal inclusions and other cool & weird stuff found in opals
let see what is inside

recently I was playing with my opals and I've found something odd
this opal is really unusual Welo with odd honeycomb pattern mix but it's not about the pattern
there are funky 'dots' inside opal and most of them are pinkish in color
I've seen the 'dots' in opal before but not as much as here and dark or black

20x Zoom




here with different lightning and visible honeycomb webbing structure




80x Zoom
I managed to capture the fire




every 'dot' is on different dept so I was unable to focus
only 1 object is in focus and appear to be semi transparent




here the best shot at 350x Zoom
'alone in space'




and here few more with fire & pattern at 20x Zoom

1st - reverse effect
2nd - 'normal'

These little dots are not bubbles. I have had many and one just the other day that have these tiny inclusions of iron or something I have had them in black and the ones lately have been red in color. Like tiny red polka-dots floating in water, and are best viewed when the opal is fully hydrated and water clear under a good strong loop. Really cool pics thanks for sharing. I had some good pics but lost them all because I had no back up when I lost my OS.

yes Toby black/dark dots are more common but I wonder what is that 'red' stuff

here are other Welo with 'classic' black dots




and here Aussie with dark dots inclusions



& 80x



additional 1 other cool shot I did 'the full moon honeycomb'
enjoy

Ive seen similar in Aussie Opal, kinda looks like leaf matter when studied, but I think they are bacteria.

I think in Welo it could be ash, bacteria or some mineral. It kinda looks like it has been shot, not deposited or grown.

One of the Australian cabs that I'm working on has 2 little "dendrites" in it. These are bacteria? I wondered if they might possibly be manganese oxide, iron oxide, or organic carbon? They look similar to the dendrites seen in some agate materials.

I think bacterias are too small
this is organic / plant material
Welo & Aussie can have dendrites which are quite cool

I think bacterias are too small
this is organic / plant material
Welo & Aussie can have dendrites which are quite cool

It's very interesting to contemplate what the earth looked like at the time this material was formed, and what creatures crawled around at the time (and may have gotten caught in it)....lol.

I've heard conflicting reports about when exactly this Welo material was formed, how old do you guys think it is??

Some people actually say it's only a couple thousand years old, while others say millions.

I founded one more with 'black dots' and I was surprised because I have this opal for quite long and never know there are 'dots' , before I didn't even checked this opal with magnifier because it's transparent crystal and you don't see any 'dots' with naked eye (the dots are super tiny)
I thought there are no 'inclusions' in the opal but now appear that there are thousands
also this one is odd because most of the dots are 'square shape' (photo 3)

photo 1. zoom 20x / light from the top
2. zoom 20x / light from the back
3. more zoom / square shape (sorry for poor quality)












****


and here some other cool pix 'Dendrite Pattern'

question >
is it possible that this dendrites are like 'footprint' of honeycomb/tubes/fern... patterns ?
because most of this tube / cells or webbing structures in Welo are looking like that but there are no dendrites

photo1 . dendrite pattern + inverted colors
2. best shot 'fern shape'
3. zoomed dendrite (sorry low quality again)

I'm glad we are discussing inclusions in Welo again, it fascinates me!

I am of the opinion that there still may be many many undiscovered types of Welo inclusions, simply because the deposits are sprinkled all around the countryside, not just in one specific spot there, (although obviously there is one main Welo deposit area) and ground conditions and mineral deposits are quite varied from place to place, maybe even different a few feet from one another.

I haven't handled hundreds of kilos of this material of course to get a wide varying sample of many specimens, but of the Welo I have handled, I've seen many interesting things "suspended" in this material.

I have not read all the scientific studies, so maybe I'm repeating things already known and classified, but I still maintain that part of the hydrophane structure in this opal consists of small tube like structures in "some" specimens. Why? Because I've seen them.

Ever notice how some pieces of rough literally stick to your partially wet finger if they are dry, while others don't? It's weird.

Why are some pieces more hydrophane than others? Why do some recover quicker from getting wet than others?

Regarding those black dots that seem to be suspended in the material, I've observed that some of these "dots" are just that, material or minerals (organic or other stuff) seem to get frozen in the rough as it solidifies, while others seem to be those tiny little tubes that are clogged with dirt in their ends.

I've had a couple pieces where these "tubes" seemed to have sucked up dirty water and you could literally see all these little strings inside the opal pointing towards the center of the nodule, very interesting.

Some of the pieces like shown in the pictures here are actually tiny crystalline structures, I wonder if those are formed inside the opal itself during some kind of electrochemical process, or if they are pre-existing and just got caught up in the suspension and remained there forever.

It would be interesting to get a analysis of what those little crystalline inclusions are, if we were looking at a sapphire for example, I would suspect zircon inclusions.

there are plenty of undiscovered inclusions simply because most people don't look for them,
also when the opal is white, inside inclusions might be only seen when soaked with water

how the inclusions are getting inside ? i'm not sure
some appear to be 'frozen' inside like you said but other types are opalized = replaced by opal

before I thought the fern/tubes are opalized 'ferns' and other plant/organic material which was replaced by opal silica ..etc
but I had welo opalized branch (small piece) where the same fern/tube structure was inside (without visible potch/cells)
so if this was the case the 'plant like material' could not be inside the branch !
also I founded that in many welos there are different layers and when you have 'good' rough with cross-section (split in half vertically) you can see different layers of fire (in case of welo with potch it's easier to determine where is the bottom and see the layers)
* this is quite useful for good pattern orientation
even though there are tubes in each layer there are different pattens in every layer
in most cases the layer of fire are 'straight' and parallel to each other(horizontally) and the tubes are going 'up' vertically
this layers are showing how the opal grow (a bit like layers in quartz crystal), 1 layer can be very thin and the next one thick both without potch and webbing and the top 3rd one can have visible webbing ..
why the opal grew this way ? why there are 'tubes' ? I don't know

* 'the dots'
I though that maybe this dots are coming from the water but I don't think there are small enough to be soaked
although we know how good welo are for dying so who knows what 'they can suck it'
Welo are like leeches

Those fern inclusions are spectacular OpalS, and the square cubes mean the inclusions are something in the cubic crystal system, most likely pyrite.

And the ISG was merely trying to figure out what was causing the plumes, and I believe the determination was iron oxides, but why they formed as they did was not investigated.

thanks Pink

I hope someone will find out soon .. but I don't think it will ever happen

Sorry for the barrage of questions, it's just how my mind works, I need to know things....lol.

I think my interest in inclusions stems from my love of sapphires, particularly Sri Lanan sapphires where the inclusions "authenticate" the stone.

If you don't see an inclusion in a sapphire, or at least some "silk" it should raise red flags, especially if a really nice stone is really cheap.

I've even had synthetic sapphires that someone took the time to laser drill as if to "pretend" they were drilling out a natural inclusion, which they sometimes do in a natural stone.

At least you "acknowledge" the existence of these tubes in Welo, I've had people tell me I'm crazy, even after posting pics of stones with these inclusions taken through my 40X inspection scope.

I did have one stone that I am quite sure was actually some kind of root embedded into it, it certainly looked like organic material and not like a mineral deposit or anything, I'll see if I can find pics of it, i sold it a couple years back.

Regarding those layers you mention, I often wonder if the formation of Welo type material happens over many seasonal flood cycles in the region, each adding an opalized layer in the pocket where the opal is formed.

Some of the Welo stones I've had looked almost like Australian seam opals, while most of them seem to form in nodules.

I am also convinced that electricity plays a role in forming opals in general, and wonder if some kind of electrolysis process may take out certain minerals like iron or magnetite and cause clumps to form in an opal, where it is then frozen in time forever, who knows.

Once I perfect growing my own opal in my lab I'll let you know!!

Each type of gemstone is composed of specific elements that give each their distinctive chemical composition; ie: quartz is SiO2, silicon dioxide. Emerald, or green beryl, is an aluminum beryllium silicate as Al2Be3(SI6O18), while heliodor, or golden beryl, is slightly different as Al2Be3(Si6O16). Iolite is a magnesium aluminum silicate as Mg2Al3(AISi5O18), and jadeite is a sodium aluminum silicate as NaAl(Si2O6).

All those elements can sometimes be in the mix gemstones come from, and gemstones get their colors, as well as inclusions, from other elements being in the mix, so how do they get there?

Magma gushing to the surface forms gem-bearing igneous rock, and from magma intrusions we get pegmatite dikes, where magma, or even a hot water solution pushes into preexisting rock and melts it. The contact zone where the pegmatite intrusion and the host rock meet melts and then cools, and this is where gem crystals can form.

Pegmatite dikes generally have a high silicon content, and the melting host rock mixes with it adding other elements which gravitate together to form other gemstones, so you can have things like black tourmaline inclusions inside quartz, or hematite in opal, etc, or if there's enough of each you can find them embedded in, or sitting next to each other as large crystal formations.

Metamorphic rocks are frequently caused by the intrusion of a pegmatite dike, and are the result of great heat and pressure that causes rock to melt and reform, and it is when metamorphic rock is created that many gem crystals form such as ruby, sapphire, chrysoberyl and emerald.

All gems are colorless in their purest form. For instance, the pure form of colorless sapphire/corundum consists of one atom of aluminum, along with 2 atoms of oxygen; neither of which have color. So color has to come from something outside the basic structure, so what might be in the molten mix that would give us a ruby?

We would need a minute amount of chromium, and if it's there, as the liquid cools and the corundum is beginning to crystallize, the chromium will attach itself to the aluminum oxide molecule giving us a mixture of aluminum, oxygen and chromium, so we get ruby. If we have the 2 impurities iron and titanium, we would get a blue sapphire.

A molecule of beryllium aluminum silicate with no impurities is colorless beryl, but add chromium and it becomes emerald; add uranium and it becomes heliodor; add iron and it becomes aquamarine, so the color can come from minute amounts of other elements as impurities. There are other ways too involved to get into here, that would be impertinent to the subject matter anyway.

If the amount of the impurity in the mixture is great enough, that's the source of visible inclusions, other than any plant matter that survived the heat.

There's more to it than that, since this doesn't cover oil inclusions, or 2 or 3 phase inclusions, but hopefully those new to inclusions will get the gist of how other elements in the molten mixture get into gemstones and can affect them.

I just hope I helped more than I confused people.

[OpalSpectrum]

quick report

Welo with Roots + Top ContraLuz Fire + 'Dots'
rare unusual Mix ..



20X Zoom

nice! Can you video the contraluz? I've not seen very many.

KJ here is quick video with ContraLuz

but 1st some basic info (from my XP)
ContraLuz in Welo is not something rare !
although most CL is low grade or in white hydrophanes that is why the fire is 'hidden' and not so beautiful
btw. I'm sure most of you have some Cluz
*there is more about CLuz and I will add other examples and give more info in other topic because I don't want to change this one

this Welo has good Cluz with 'Prism' Pattern (which might be confusing)
at the beginning of the video I keep the opal in the shadow > the fire is dull (low grade)
in sunlight the fire is very nice and has rainbow colors (light source is behind the opal !)

[youtube]http://www.youtube.com/watch?v=gcgNUGPWo3Y[/youtube]

[OpalSpectrum]

Thank you Pink for the explanation on Metamorphic material.
I find most technical talk tedious to understand, but your explanation simplified some of the things in the process that I had yet to absorb in the process.

The tread here is about inclusions, and maybe somewhere it has been discussed already, but what is the fire in opals ? Are they inclusions too?

The other thing that still fascinates me is the origins of Fire Agate. Some papers have been written, but it has never been really taken through a scientific process to define the origins in definite terms.

Australian opals are type A, with a structure composed of hydrated silica spheres packed tightly together and stacked kind of like cannonballs. When light passes through the ordered, stacked planes of silica spheres, they act like a diffraction grating prism causing interference, and diffusion of light into spectral colors relating to the number and size of the stacked spheres that range in size from 150 to 300nm, along with the spaces and orientation of the planes in regard to incident light, which determines which colors we see.



Ethiopian hydrophane opals are opal-CT, having tridymite and cristobalite in their structure, which has angles instead of smooth spheres. The cristobalite and tridymite blades are stacked in close, but sometimes irregular patterns, having flat sides and hard corners that form a more open matrix that allows water to penetrate them, making them hydrophane.



Since the size, number and stacking of the spheres in opal A determines the colors, I'm still looking for papers on how the hydrophane Welos, with their open and inconsistent structure, produce the colors since I've not seen any literature on the size and number of the spheres, and they're not ordered like opal A, so if anyone has info on it, I'd appreciate it if they'd share that wish us.

I wonder why some welo have Cluz fire and other not ?
I guess this depends on how the tridymite vs cristobalite form
also some top Fire Welo are mix of both 'normal' type of fire + Cluz and I think this is 1 of the reasons why the Welo fire can be so strong and intense

A bit late in the day, I just found this interesting topic. Much food for thought.

I agree with OS, Mick and others that the inclusions in OS's honeycomb Welo almost certainly is plant material deposited dieing the opal formation. The opal seems to have a lot of 'milkiness - as does most of the opal I have seen (and have) that is not of top grade - and this milkiness rather than any equipment limitations are preventing the inclusions being observe with analytical clarity. If the stuff was mine (and I was equipped and skilled as a cutter), I'd take am offcut containing the inclusions and patiently reduce it t a slice not more than about 1mm thick containing several of the inclusions. This should remove alot all the milkiness from the section amd permit investigation of the make-up of the inclusions by both transmitted and reflected light. MY guess is that this would confirm the structure of plant material. and permit some good images of the same to be captured.

I found Pink's explanation of the structural difference between Opal A and Wello interesting and new to me (as much is). What source is that drwn from Pink? I'd very much like to read in to it more.

The 'fire in opal, once thought to be a thinfilm interference effect, is in fact a spectral dispersion caused by the regular pattern of silica spheres forming a natural diffraction grating. Uniformity of the size of the silica spheres is what createds the diffrction grating. Different sizes of sphere and angle of display cause different colours. No uniformity of sphere size and layout across significant areas and there will be no colour display. A typical size of a silica sphere in opal is 250nm, or 0.0004 mm. For a sense of scale, this is shorter than the wavelength of light - but photos of the spheres have been made using an electron microscope, which does not need light to make its photographic images.

Something inherently wrong, I think, with the notion that any opal comes/came from a volcano. If someone wants to explain I'd be happy to listen.

[youtube]http://www.youtube.com/watch?v=wYAR6EKWiOA[/youtube]Virgin Valley Contra Luz (Inclusion moves)
The fire is not an inclusion but a feature of the molecular form. Precious opal has apparently ionized during formation and has a definite grid like structure that will form prisms in the structure resulting in pure colors while all others either absorb all but one color or are refractive (oil on water colors like fire agates not rainbow pure ones except in rare cases). Crystal opals have almost no internal light interference and white opals are "confused" putting out mixed light from conflicting sources - which is why the brightest stones are triplets due to the removal of excess color layers, each which is as brighter than the whole. I've also heard it is the manganese oxidized that makes them white. The Australian Gemmologist magazine has taken a hard look at the structures found in opal more than once. Being almost as common as quartz there is no ONE formula.

Volcanic describes everything that was not the Australian basin "sedimentary" in general use. Yes it is usually formed among lava flows inter spaced with ash on around faults or springs mainly. Look at that one photo of the Wolo bed and you will see a lot of digging on one side of the fault but hardly any on the other. Like in Australia there was still a fault element involved with formation of opal, mechanical or chemical ?

I imagine if opals had a set structure, there would be phantoms found. Coalescing inward out of larger blob of silica gel would not have surfaces but would include odd mineral components forming out of the gel discreetly.

If opal was a crystal, I think that would probably be right. But it's not The SiO2 unit cells join together in a disordered way and in a delicate liaison with varying number of water molecules. These too have no crystalline structure unless cooled below the point at which they change from the liquid to the solid state. Pink's quite right; the water/silica gel (since it is neither crystal nor glass) forms spheres. If these settle in a very regular pattern, then the opal will have play of colour. A reasonable outline is here http://www.uniqueopals.ch/opal-play-of-colour.htm .

If the structure was always the same and perfect, all opal would show the same colour. But at we know, that is a usually some disorder, both in the size of the spheres and also in the physical limits of their orderliness. Hence the usually broken and varied patterns of POC - and the absence of play of colour in common opal and potch.

Here's the results of a study done on Ethiopian gem opal CT specifically, that I hadn't seen before:

Luleå University of Technology
Master Thesis, Continuation Courses Exploration and Environmental Geosciences / 2010:033

This Publication is confidential until 2011-06-01
TITLE
Characterization of Megendi/Angatosch and Delanta Ethiopian gem opal-CT

AUTHOR
Andersson, Joel

DEPARTMENT
Chemical Engineering and Geosciences / Applied Geology

SUMMARY
This study aims to describe the structure of Ethiopian gem opal-CT in order to characterize the material. Focus is made on gem opal-CT originating from Megendi/Angatosch in Gonder and Delanta in Wollo/Wello, both situated in the Amahara region, Ethiopia. This study also aims to describe the opal host rock by means of petrographic investigations in order to better understand the geological setting that hosts this poorly studied gem material. The analytical methods used in the study are optical microscopy, Raman spectroscopy and Extreme High Resolution Electron Scanning Microscopy. The dominant rock type is a mafic extrusive rock with trachytic (sanidine) and amygdule texture and contains phenocrysts of clinopyroxene, suggested to be a trachybasalt belonging to the Cenozoic “trap series”. The opal is precipitated from hydrothermal solutions within the amygdule accompanied by iron hydroxide situated at the rim of the amygdule, which precipitates before the formation the opal. The structure of the opal is built up by nano-grains with an average diameter of <10nm, probably 5-8nm. Such a small particle diameter in opal is documented here for the first time. The nano- grains aggregate to form larger pseudo spheres, fundamental for the opal-play-of-colour to occur. The pseudo spheres are hosted in a matrix that react more heavily on 10% HF for 30 seconds than the pseudo spheres them self. This is documented here for the first time in gem opal-CT and indicates that opal-CT is a two phase material. The study shows that Ethiopian gem opal-CT is a very interesting and complex material from a geological, mineralogical and gemmological point of view.

ISSN 1653-0187 / ISRN LTU-PB-EX--10/033--SE / NR 2010:033

http://epubl.ltu.se/1653-0187/2010/033/index-en.html

I like their use of the term 'pseudo spheres' for the spheres in Ethiopian opals since they're nothing like the spheres in Aussie opals.

Interesting, thanks for sharing. My favorite paper about Virgin Valley physical geology is also a Masters Thesis. I wonder.. if the small spheres make psuedo spheres for diffraction, what do they do to have the contra luz effect. Maybe they never make spheres and it is a more or less uniform gel with "quantum"spheres or "discreet diffraction" or what ever the pass thru not reflected color is. Refraction?. I'll quit wondering and look it up if nobody else has the paper yet with the answer on the tip of their keyboard. I really want to have a set of triplets made (not just one but good rough dropped through the wire saw for a production run of more than just a single chunk.)

[OpalSpectrum]

'the forest'






this is 1 of the best examples of Welo with 'plant/fossil' I've seen .. there are over 30 'stalks?' .. and it's 100% stable no cracks/crazing
btw. the light is behind the opal to show what is inside

I dont understand how plants can get trapped inside. Wouldnt they just burn up as it becomes opal?

I have to agree having read the scientific description of the how and why of formation for E opal. NOT PLANTS. Internal mineral growths which would be obvious with magnification. Roots have branches and go to the outside in Virgin Valley or where ever that opals forms on/in casts after plants can be photographed. Also cabs can be made from stable opals that form around inclusions. The inclusion itself does not make the opal more or less stable. It's just that most of them come from a less generous environment. They still produce color the same way opal is.

... The inclusion itself does not make the opal more or less stable. ..

the 'roots' inclusions in Welo often make opal less stable .. in most cases the inclusion will create crack/crazing when soaking in water
I've cut couple different welo with roots but most cracked .. there is big risk cutting welo with 'roots' ~!

RR. I think these are 'opalised plants' not real plant fossil like in amber

i'll make video and post later

greets

Somewhere, I think Treasure Opals posted an article about plant matter showing up in opals, so apparently not all of it is mineral oxides, but I have to agree that roots should have side shoots, so I'm wondering what they could be. It's a lovely specimen OpalS, and you did a nice job on it. Congrats on it staying intact, too. The inclusions look like they're floating around in water.

...

RR. I think these are 'opalised plants' not real plant fossil like in amber

That's what i cant wrap my mind around. So that is a "mineral growth" such as a plume in agate?

Why can't it be what's left of the root, such as ash that has stayed in place, encapsulated.

OK I did quick video , also have 1 more cool photo showing the opalescence (?)
enjoy

video >

[PinkDiamond]

Good job moving this one OS! Looks great.

[OpalSpectrum]

- Digital Photomicrography for Gemologists - http://www.gia.edu/gems-gemology/summer ... emologists

good info , tips & great photos

[opalcreations]

I remember back in the day the surprise of finding organic material inside a Welo opal for the first time, and the discussion that then followed in which everyone told me it was not organic, but just manganese inclusions. Then there was then the debate about how many years it takes an opal to form....lol.

After all I've read, and all I've seen (not that I'm some kind of expert or anything!) I'm still not convinced Welo opal is "all" millions of years old.
I personally think it may still be forming in the ground as we speak, and some of the deposits are quite new, and yet many other deposits may be millions of years old, who knows!
(God knows...lol)
Chris

[kjsspot]

Wasn't there a topic once about a guy who grew opals in his garage?

[opalcreations]

Yup, there was, and I was working on a formula to try it myself.....whoohahaha, mad scientist laugh, hehe :

[kjsspot]

ha! Ya, and it wasn't taking him millions of years...