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PostPosted: Wed Jan 30, 2008 2:40 pm 
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Hi cutter,
Moldavite, Obsidian and manmade glass are all glass and will exhibit similar characteristics. It may require study with a microscope to help in separation, study of the surface and inclusions. Absolute separation of glasses may be difficult unless it has some obvious features (like mold lines on a piece of molded man made glass or stubby needle inclusions in obsidion).

I don't think it is weird at all to focus on one material. Aqua is certainly a good one. Please post some of your cut stones in the faceting section!

You might also keep in mind for future reference other gems that can imitate Aqua. Synthetic Spinel and sapphire triplets and doublets, glass and even plastics. There are even triplets of beryl or quartz with a colored cement joining the layers. These might not pop up very frequently though. Try shining a penlight at the girdle to check for triplets, or immersing in water or mineral oil. Now I can imagine that each new stone you will be pressing against your forehead!

Hope that helps-Carrie :D


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PostPosted: Wed Jan 30, 2008 2:51 pm 
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Hi,

Obsidian could be a candidate, but remember that gemstones are guilty until proven innocent. Transparent green obsidian is rare and has an upper SG limit of 2.42 in my books.

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PostPosted: Wed Jan 30, 2008 3:13 pm 
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Carrie wrote:
Hi cutter,
Moldavite, Obsidian and manmade glass are all glass and will exhibit similar characteristics. It may require study with a microscope to help in separation, study of the surface and inclusions. Absolute separation of glasses may be difficult unless it has some obvious features (like mold lines on a piece of molded man made glass or stubby needle inclusions in obsidion).

I don't think it is weird at all to focus on one material. Aqua is certainly a good one. Please post some of your cut stones in the faceting section!

You might also keep in mind for future reference other gems that can imitate Aqua. Synthetic Spinel and sapphire triplets and doublets, glass and even plastics. There are even triplets of beryl or quartz with a colored cement joining the layers. These might not pop up very frequently though. Try shining a penlight at the girdle to check for triplets, or immersing in water or mineral oil. Now I can imagine that each new stone you will be pressing against your forehead!

Hope that helps-Carrie :D


yeah I was just reading up on obsidian. Interestingly there was one in google pics that looked a lot like this one. I think in deciding between obsidian and glass it's really just a question of natural glass vs man made glass and without a microscope I doubt I'll ever know for sure. A good gem microscope has been on my list of items to get for a while.

What's the RI of synthetic spinel? Interestingly, I've bought a few so called "lab stones" over the years to compare to real aqua and I have yet to see one that even looks convincing. They may look convincing on their own but when you put them in a mix of real aqua (I have a fairly large collection from all over the world) they immediately jump out at you visually as suspect. The RI's are all incorrect as well. This "thing" is the first thing that's fooled me visually in years. It could easily pass as madagascar or mozambique aqua. It has all the visual traits of a real aqua.

yeah when my wife sees me putting stones on my forehead she's probably gonna call the men with the butterfly nets to take me away even sooner.
I'll have to do that test when she's out of the house.

I'll get around to putting up some pics sometime. I started out as a carver and moved into flat faceting although I have to admit I hate to think in xyz terms because I like curves so the direction I'm getting into is a combination of flat faceting, curved faceting, grooves, shapes and carving.
A lot of my tools are homeade. Sometimes I start with an already cut stone depending on what I'm trying to do.

To me, the tools are all just means to accomplish the vision I'm a big fan of what Richard Homer is doing in Aquamarine with curved faceting and what some of the other carvers do.

I'm glad I found this forum though. I just made a post asking about how other people measure specific gravity because I have a homeade way to do it that is prone to small errors.


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PostPosted: Wed Jan 30, 2008 3:19 pm 
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Doos wrote:
Hi,

Obsidian could be a candidate, but remember that gemstones are guilty until proven innocent. Transparent green obsidian is rare and has an upper SG limit of 2.42 in my books.


Hi There. Thanks for that info. I agree with what you're saying. My SG measurements are prone to small errors because I have a sort of weird way of doing it. For now I'll call it the most stunning piece of glass I've ever seen.


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PostPosted: Wed Jan 30, 2008 3:36 pm 
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Just wait till your wife sees you trying Visual Optics! You hold the gem with its table almost touching your eyeball, then hold a pen light a little ways away. Look through the stone and you will start seeing little rainbows. Double (sometimes overlapping) rainbows will mean it is DR. It can also give you other info. Harder to do on the lower RI gems. I am practicing now to get better at it. You look like an idiot doing it (or maybe its just me) but it is a great no-equipment technique.

I do SG the same way you do, Hydrostatic weighing. It can be tough to get a really accurate measurement, especially on smaller stones. I just invested pretty heavily on a better scale that should give me sharper SG measurement on smaller gems.

Looking forward to seeing your gems!


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PostPosted: Wed Jan 30, 2008 4:21 pm 
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Carrie wrote:
Just wait till your wife sees you trying Visual Optics! You hold the gem with its table almost touching your eyeball, then hold a pen light a little ways away. Look through the stone and you will start seeing little rainbows. Double (sometimes overlapping) rainbows will mean it is DR. It can also give you other info. Harder to do on the lower RI gems. I am practicing now to get better at it. You look like an idiot doing it (or maybe its just me) but it is a great no-equipment technique.

I do SG the same way you do, Hydrostatic weighing. It can be tough to get a really accurate measurement, especially on smaller stones. I just invested pretty heavily on a better scale that should give me sharper SG measurement on smaller gems.

Looking forward to seeing your gems!


HA !

her favorite thing is holding one close to her eyeball and twirling it around while she watches 30 TV's through it. She just likes to look at it and wear the finished products....no interest in how it gets that way.

I especially like the light vibrant subtle colors from Pakistan/Afghanistan and that only goes for 5 to 20 per carat so you don't have to pull your hair out if you goof one up. for some reason (rarity I guess) the darker blues are what bring the big bucks but I prefer the medium color range which is lucky for me because it's hard to afford the deep blue santa maria stuff....although I am hoping to take a trip to Brazil to find some HQ rough from a local one of these days.

I have a pretty inexpensive digital scale but it measures to .001g and I've been very happy with it. I don't work on small stuff under 4 carats or so, so it's not the issue. The problem is my goofy jerry rig for the hydrostatic weighing.

I'm not going to recut this stone...the guy I bought it from said he'd give me my money back but I want to keep it as a curiosity. It's 4.5 carats and I only paid $35 for it ....someone spent several hours cutting and polishing this thing though so the great cut is worth more than that. It will go in my "great fakes" box or I'll make it into a ring for my wife. She loves it and was disappointed to hear it's not a real aqua. Maybe it is obsidian. Maybe I'll figure it out for sure some day.


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PostPosted: Wed Jan 30, 2008 4:30 pm 
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I personally would hang on to that as a study stone and do some more tests as you get access to the equipment. I don't know where you are located but there may be a forum member near you with more equipment. You have pretty much made your ID on it but I always like to have several bits of data to help with confirmation. Certainly hold on to it till you can look at it through a good scope. There is a world of difference under high magnification and it may show you inclusions to look for in the future. Just a thought.


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PostPosted: Wed Jan 30, 2008 6:32 pm 
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Hey cutter, just thought about a simple tool you might like. Dr. Hanneman, a member of this forum, created different gem filters. One is an Aquafilter used to help separate blue colored stones. No filter is absolutely diagnostic but it could be a handy tool, especially when sorting through a parcel or rough.


They carry the filters at http://www.prettyrock.com listed under Gemology Tools.


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PostPosted: Wed Jan 30, 2008 8:15 pm 
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Carrie wrote:
Hey cutter, just thought about a simple tool you might like. Dr. Hanneman, a member of this forum, created different gem filters. One is an Aquafilter used to help separate blue colored stones. No filter is absolutely diagnostic but it could be a handy tool, especially when sorting through a parcel or rough.


They carry the filters at http://www.prettyrock.com listed under Gemology Tools.


ok thanks for the tip Carrie. I'll check it out especially since my work mostly consists of just telling if it's aquamarine or not aquamarine.


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PostPosted: Wed Jan 30, 2008 11:32 pm 
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Do you think this could be obsidian?

no


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PostPosted: Fri Feb 01, 2008 5:13 pm 
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Barbra Voltaire wrote:
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Do you think this could be obsidian?

no


I think that's probably correct but I wanted to post a picture of a blue green obsidian because I had never seen one until I looked into this. There are a lot of pictures in google image search. Some look very much like Aquamarine.


Image


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PostPosted: Fri Feb 01, 2008 5:31 pm 
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I would be wary that some sellers might use the term Obsidian to make some man made glass sound more appealing.....

Maybe I am too cynical... :wink:


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PostPosted: Fri Feb 01, 2008 5:35 pm 
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Carrie wrote:
I would be wary that some sellers might use the term Obsidian to make some man made glass sound more appealing.....

Maybe I am too cynical... :wink:


Personally I'm as convinced of the reality of blue obsidian as I am of sprite or 7-up green moldavite. It's fake.

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PostPosted: Fri Feb 01, 2008 5:53 pm 
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brimsjewelry wrote:
Carrie wrote:
I would be wary that some sellers might use the term Obsidian to make some man made glass sound more appealing.....

Maybe I am too cynical... :wink:


Personally I'm as convinced of the reality of blue obsidian as I am of sprite or 7-up green moldavite. It's fake.

J-


I guess there is a lot of controversy about it. Here's something I was just reading with the link it came from. I don't know this person but maybe someone here does.

"Facet grade blue, green, and yellow obsidian
OK, lets settle this once and for all. There is pale and deep emerald green translucent obsidian here in Oregon. There is also deep blue, pale yellow, and very pale brown. All Im describing is translucent enough to facet. I have specimans I have recovered myself and will be willing to subject to reputable testing. Lets get a consensus as to by whom....
Let me tell you a little about myself. As a boy I had a pure blooded Chippewa Indian friend who had a translucent green arrowhead. Family tradition held that it came from "utum paints", far to the west. I was always intrigued by this. Years later I discovered that "utum paints" is Shoshoni for "arrowhead land" and was renamed Glass Buttes, Oregon. As an adult I began searching, and have located three good deposits of green, one small deposit of blue, and areas that occasionally produce a piece of pale yellow or lite brown. These colors really do exist although they are very hard to find, and other than the green, were located by accident, just happening on it.
I also have encountered pale green, lite blue, and aqua facet grade obsidian in the gem markets of Shenzhin, China; but dont currently possess any samples of these materials. The inclusions in the rough made it clear it was natural glass.
The chase for this material has led me in some strange places, and claimed years of my life; but I am exasperated by the faking of this material to the point where many dont believe that it even exists. It does, and is very rare.
Lets see if we can get a consensus here, that will prove that this material does indeed exist and satisfy the skeptics. I have both faceted and rough examples, and will send them to the appropriate parties to be tested....."

http://www.rockhounds.com/rocknet/archi ... 4914.shtml


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PostPosted: Fri Feb 01, 2008 5:57 pm 
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Send it to GIA or AGTA


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