October 27-28—SACRAMENTO, CALIFORNIA: 82nd Annual Gem, Jewelry, Mineral and Rock Show; Sacramento Mineral Society; Sat. 10-5, Sun. 10-4
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 Post subject: Newby question about a specific inclusion type
PostPosted: Sat Nov 19, 2016 6:44 am 
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I've been a lifelong rock hound but recently acquired a microscope and so I'm learning to identify inclusions. The following photos were all taken of different inclusions of the same type from one greenish-blue Sri Lankan spinel rough. I had to oil up the stone so I could see into it and took the photos with my iPhone. The light source is polarized. Can someone help identify the inclusion type? It looks like a rounded crystal with a sailboat sail sticking out of it. The piece of rough has many of these and each photo is of a different one.

Thanks for looking,

Ken

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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Wed Nov 23, 2016 1:41 pm 
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my first impression is "are you sure it is a spinel?"

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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Wed Nov 23, 2016 4:30 pm 
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Nathan Renfro wrote:
my first impression is "are you sure it is a spinel?"


Nathan, thanks for the reply and for keeping me honest

I went back to my rough and looked at it again and I think you're onto something. I bought a kilo of rough at Tucson gem show about 30 years ago but never had it cut. Now I see a few pieces mixed in that have an obvious rind, so it's probably tourmaline. About 675 grams is an intense green-blue or blue-green color, quite bright and beautiful looking. The remaining 400+ grams are purple-pink or pink-purple, also nice looking.

I just assumed spinel as the bag of rough was in my rspinel rough box. Good catch. So I can see two-phase and three-phase inclusions as well as a variety of crystal shaped inclusions but the one I picture above have me baffled. Any ideas?

Grateful for any help.


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Wed Nov 23, 2016 5:15 pm 
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Same question !
These look like bubbles and melting traces...


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Wed Nov 23, 2016 8:04 pm 
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Isi wrote:
Same question !
These look like bubbles and melting traces...


:D :D :D oh my. I never considered glass. Tucson 30 years ago had quite a few sellers of questionable material just as today. Thanks Isi, Nathan may have been thinking glass as well but I didn't get the hint if he was :oops:

Well let me verbally think this through in my post to follow...


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Thu Nov 24, 2016 5:55 am 
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Let me verbally think this through:

Ok, I can see natural crystal faces on some of the rough, but it is possible to fake this so these are not conclusive of natural.

I can see rounded inclusions that are either glass bubbles or rounded solid material inclusions. The round inclusions mostly have thick walls with what looks to be a hollow center that may be filled with gas or liquid. Most of the round inclusion thick walls have their own inclusions embedded within the wall. Sometimes smaller rounded inclusions, sometimes flat faced crystals, sometimes dark flecks of something I can't identify. It appears that some of the rounded inclusions with thick walls have an inner cavity that has a negative crystal form.

I can see a few two phase inclusions which appear to have one or more thin walled bubble shapes moving about within what appears to be a fluid filled cavity. The fluid appears to have brown or dark colored particles but I can't see evidence of crystal shapes at 150x.

I can see growth tubes with tiny anisotropic crystals within the tubes.

also a few new photos with inclusions...

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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Thu Nov 24, 2016 1:22 pm 
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The following photo shows another interesting inclusion. A tube, possibly containing fluids and also containing many tiny perfectly shaped anisotropic crystals standing side by side. The tiny crystals vary slightly in height but are otherwise remarkably similar in size. Each doubly terminated.

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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Thu Nov 24, 2016 4:43 pm 
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I think you complicate things too much in your observations. To me it just looks like glass with bubbles. I don't see what kind of natural spinel - or any other natural stone for that matter - might show this type of inclusions. Of course without seeing the stone it is just an impression. A few further tests, if you have some tools, might be more conclusive. Could be another artificial product too.


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Thu Nov 24, 2016 10:27 pm 
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Touch the stone to your lip. Is it cold or warm?


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Sat Nov 26, 2016 4:28 am 
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dchallener wrote:
Touch the stone to your lip. Is it cold or warm?


dchallener:

I would say cold (not like an ice cube, but much colder than room temp).

Not sure if that's good or bad but I didn't let my wife see me kissing a rock. She would think that I've finally lost my last marble.

Isi:

Thank you for the feedback, you have pretty good observation skills.

All, I find myself with "egg on my face" (feeling embarrassed) after taking my bag of rough to a local gem lab for opinion. They looked my rough over pretty well, tested a number of pieces, separated out a few pieces of watermelon tourmaline and declared the remainder to be varieties of beryl. I was pretty shocked and never would have guessed beryl. In my rock hound log book I recorded the purchase nearly 30 years ago at the Tucson Gem show as a kilo of tourmaline rough, price $250. I'm pretty sure that's how it was presented to me when I purchased it. The GG at the lab pointed out dozens of typical beryl inclusions including two phase and three phase and also tested RI, pleochroism and SG and did a couple more tests that I wasn't familiar with.

Understanding what mineral I'm looking at will certainly help my learning. I'm now looking at inclusions in some of the stones. Some pretty interesting inclusions and I'm able to identify most by matching them up to internet beryl inclusion images.

Thank you all for the assistance and Isi, I would never had visited the gem lab if you had not challenged my conclusions, thank you.


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Sat Nov 26, 2016 7:50 pm 
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If warm, it would be glass. If cold, it is probably not glass.


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Sun Nov 27, 2016 5:39 am 
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dchallener wrote:
If warm, it would be glass. If cold, it is probably not glass.


I never knew that, it should come in handy in the future. Thanks dchallener :) The cold feel does match what the gem lab determined.

I have much to learn and too few hours per day.


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Sun Nov 27, 2016 2:51 pm 
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My pleasure !
Good that this discussion induced you to go and see a lab, good too that you have one not too far from your place, that definitely can help. A few right physical tests will give safer answers than interpreting pictures of spherical inclusions.


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Sun Nov 27, 2016 9:41 pm 
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rocksarefun wrote:
I had to oil up the stone so I could see into it

I think this may provide the answer. Bubbles in oil that penetrated surface-reaching fractures, perhaps?


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 Post subject: Re: Newby question about a specific inclusion type
PostPosted: Mon Nov 28, 2016 9:32 pm 
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Stephen Challener wrote:
rocksarefun wrote:
I had to oil up the stone so I could see into it

I think this may provide the answer. Bubbles in oil that penetrated surface-reaching fractures, perhaps?


Stephen, thank you for the idea, one that I had not considered yet. I need to read up on oiling beryl, just so that I can recognize it if I ever encounter it in a stone.

From my time on Friday with the gem lab GG and also from time spent on the phone today with a tech. from a NY based lab, I have learned quite a bit about bubbles in gemstones. I'm pretty sure I'm not the bubble expert, rather I now have enough knowledge to get into trouble. :mrgreen:

If a single air bubble or more than one is located in a gemstone (cut or rough) it tells us some things.
1. The stone is made of glass or another synthetic material or,
2. The stone fissures have been filled with oil, glass or another treatment and,
3. The stone material or treatment was exposed to air during it's manufacture/assembly.

All air bubbles are bubbles but not all bubbles are air bubbles. Sometimes bubbles contain something other than air.

Types of bubbles:

1. Air bubbles (filled with air)
2. Gas bubbles (filled with CO2 for example)
3. Liquid bubbles (filled with salt water for example)
4. Solid bubbles (spherical crystals)
5. Two phase bubble with air or gas along with liquid
6. Two phase bubble with air or gas along with solid
7. Two phase bubble with liquid and solid
8. Three phase bubble with gas, liquid and solid

Because air is not found in rocks or dirt or minerals or deep earth, air bubbles are never found in natural stones unless they are treated with air bubble containing substances.

However, natural minerals can have spherical inclusions of type 2-8 along with non-spherical inclusions of course.

My final conclusion at this point is that an air or gas filled bubble cannot exclusively be used to rule out a natural stone origin because we can't tell whether we're looking at an air bubble or gas bubble just by looking. Other conclusive tests are necessary.

One last photo of one of the three phase bubble inclusions with crystals, fluid and bubbles.

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