Colored fasceted stone with striping

[mikec0703]

I have an opportunity to buy two beautiful fasceted stones from my sister. She got them at a gem and mineal show in Denver. She was told they they are from Afghanistan and that they are bi-chromic Sapphires, but have never seen anything like them. They are purple in incandescent light and a lighter blue in sunlight. In blacklight they are almost clear. The red stripe in the smaller stone (1/2) really stands out. The larger stone (3.5ct) has several red stripes. They are supposedly cut from the same rough stone. Any idea what these stones are? I think they''re pretty to look at, but have no idea what they''re worth. She paid $300 for both. ANy guesses would be appreciated. I am a collector of tourmaline and natural crystals, but have never gotten into the cut precious/semiprecious stones. See the picture I attached. Thanks and have a good day.

 

[Arcadian]

I can''t even fathom a guess because thats pretty difficult to do from a picture.

If you''re not sure and don''t have the tools yourself, you should look for gemologists in your area that have the equipment to test them out. Under the Resource tab at the top of the page, you can see if there''s any appraisers in your area that you can call and talk to.

HTH


-A

 

[mikec0703]

I appreciate the advice. Usually I just buy rough crystals ( mostly Tourmaline, quartz and citrene) for my little collection and have always been intreagued by inclusions and rutilated pieces. I guess that''s why these two caught my eye. I''ll post what they are when I find out for sure. See ya....thanks

 

[T L]

Is the luster very glassy or waxy?

 

[Jim Rentfrow]

Have a jeweler do a quick RI check on it. I have seen sapphires before like this but the stones can really be anything that has color banding, which is a lot of different species. While a RI wont totally rule out simulants and other things it is a good place to start.

 

[RevolutionGems]

Hi Mike,
I have a sapphire from Pakistan that looks something like this. It is blue and red and does do some interesting color shifts in various lights. Zoned just like the stones you posted but a little different color. Very sleepy too. I''m not sure if mine was ever heated to burn off the silk.

Just looking, I would say they probably are as advertised but you''ll want to get them check to be sure.

 

[Barrett]

I would wager that your sapphires are actually from pakistan like Jeff''s..those kagan valley ones and that area in general regularly produce sapphires in the blue and purple range that have all kinds of strange things in and on them..they form in graphite or around graphite..and graphite does some stange things..just a guess...never seen sapphires from afghanistan except some opaque specimens and don''t remember any of Vincent''s or Bowersox''s trips going to sapphire deposits there..just a guess..could be way off...a $50 agl fast track could give her/you peace of mind and keep any expensive testing cost down to a minimum

 

[LD]

I defer to everybody above as I''m sure they''re right but my first thought when I saw them was "Fluorite". I own several Fluorites that change colour from a royal blue to a rich purple. Fluorite also can have stripes and distinct colour bands. They''re probably Sapphires but in case you get them tested and they''re not, it might be worth thinking about Fluorite.

 

[T L]

Date: 2/26/2010 4:26:07 PM
Author: LovingDiamonds
I defer to everybody above as I''m sure they''re right but my first thought when I saw them was ''Fluorite''. I own several Fluorites that change colour from a royal blue to a rich purple. Fluorite also can have stripes and distinct colour bands. They''re probably Sapphires but in case you get them tested and they''re not, it might be worth thinking about Fluorite.

I thought fluorite too. That''s why I asked about the luster.

 

[gsellis]

Yes, have them checked, but don''t fret too much about unless told otherwise. Sapphires can zone. I have not seen rough like that, but the Australian parti colors can do the same. I keep this link because one day I want to cut a couple of these when he has them.

Australian Facet Rough - Sapphires Currently on the link, stones 806, 807, and 811 are prime examples. And I think I have a North Carolina sapphire that shows some zoning, which is rare from what I have found. No pic as it is uncutable and in jars with many.

 

[T L]

Sapphires can zone, but this is more like a bicolor phenomena with the color within a very defined stripe.

 

[lelser]

Date: 2/26/2010 5:45:37 AM
Author: Arcadian
I can''t even fathom a guess because thats pretty difficult to do from a picture.


If you''re not sure and don''t have the tools yourself, you should look for gemologists in your area that have the equipment to test them out. Under the Resource tab at the top of the page, you can see if there''s any appraisers in your area that you can call and talk to.


HTH



-A

They look much more like Fluorite to me. Fluorite will scratch if you look at it funny (Mohs 4) and is generally a poor choice for jewelry. It''s also not usually an expensive stone.

If you can do a scratch test on a pavillion facet that will tell you right away it''s not sapphire. Your sister may object, though.

 

[chrono]

My initial thought was some sort of colour zoning in a sapphire but the more I looked at them and thought about it, it could be fluorite too. A quick RI test should rule out one or the other.

 

[Barrett]

"Fluorite will scratch if you look at it funny "...hehehehehe

 

[RockHugger]

Ditto to the scratch test. I use a needle and try to scratch a facet then look under a loup for the scratch.

 

[mikec0703]

Thanks for all the info. I loke looking at a lot of the posts on here just to see the speculation. Really quite fun and one of the best and informative gemstone sites on the net, ok, it''s actually the only one I''ve been on, but I like it.
I will definately get them tested and get back with all of you with the mystery solved hopefully. She has actually decided to just give them to me, so that was nice of her. I may design some sort of pendant to keep the two stones together. If they are flourite they are not worth $300, but if they are indeed sapphires they should be worth a lot more. Visually there are no inclusions or cracks, just the red color bands. Like they say: ya pays your money and takes your chances. Thanks for all the input. Will update later. Mike

 

[Stone Hunter]

They are very interesting looking! More of fascination stones than a jewelry stones! But they could look cool in a pendant.

TFS

 

[mikec0703]

The stones were idintified by a local gemologist as Tanzanite. He said he has seen some rough crystals with red zones, but had never seen a faceted one with the sriping preserved. My only problem now is how to showcase them. I wish I had two of the smaller stones so I could do a pendant and earings. Thinking about a pendant with both stones. I''d like to keep them together since they were obviously cut from the same rough. Thanks for all of your comments and help. Mike

 

[chrono]

Mike,
Glad to hear that you’ve got a definitive answer to your question. Since the stones are tanzanite, just make sure your jeweller understands their thermal sensitivity and cleavage before agreeing to let them be set.

 

[RockHugger]

Tanzanite? Crazy lookin'' tanzanite! But hey, if he did the tests and said thats what it is, then thats what it is I guess.

Enjoy them!!!

 

[LD]

Date: 3/15/2010 3:59:16 AM
Author: mikec0703
The stones were idintified by a local gemologist as Tanzanite. He said he has seen some rough crystals with red zones, but had never seen a faceted one with the sriping preserved. My only problem now is how to showcase them. I wish I had two of the smaller stones so I could do a pendant and earings. Thinking about a pendant with both stones. I''d like to keep them together since they were obviously cut from the same rough. Thanks for all of your comments and help. Mike

Mike - how did the gemologist test the stones? Whilst you can get zoning in Tanzanite it''s not common and certainly NOT common in the colourways you''ve shown us. For example, the electric blue colour is something I''ve never seen in Tanzanite.

Is there any chance you can take the gems to somebody else as a double check?

IF they are Tanzanite then I''m sure you know that you must take great care when setting them? i.e. heat and pressure can crack Tanzanites by somebody who is less than experienced (and even experienced lapidaries have been known to take deep breaths before working with Tanzanite)!

 

[T L]

Date: 3/15/2010 4:34:34 PM
Author: LovingDiamonds

Mike - how did the gemologist test the stones? Whilst you can get zoning in Tanzanite it''s not common and certainly NOT common in the colourways you''ve shown us. For example, the electric blue colour is something I''ve never seen in Tanzanite.

Is there any chance you can take the gems to somebody else as a double check?

IF they are Tanzanite then I''m sure you know that you must take great care when setting them? i.e. heat and pressure can crack Tanzanites by somebody who is less than experienced (and even experienced lapidaries have been known to take deep breaths before working with Tanzanite)!

I agree, I have never seen banding like that in zoisite. Gemologists can make mistakes. I think it''s a good idea to get a second opinion.

 

[mikec0703]

Thanks for the replies, now you have me wondering. He did hardness (6.5) and density (3.3) tests is all. They actually have a more blue/purple/violet hue, depending on the lighting, but the bands stay red or maybe Very dark purple. . Yes, unusual, but what else has that hardness and density? If they are in fact Tanzanite, any idea of the value? I think since they are already cabicons, I will not cut them and will ensure whoever sets them knows what they''re doing. Thanks for the great advice. Mike

 

[chrono]

Another simple check is to use a dichroscope to check for pleochrosim in tanzanite

 

[RockHugger]

refraction...with hardness and density, that should tell you right away. I wonder why he didnt check the RI.....thats usually the first test to do.

Fluorite is that density, and if he did a simple scratch test then its not very accurate to ID a stone.

I am thinking fluorite now. I wish you had an RI.

 

[Barrett]

hmm..tanzanite from afghanistan with red lines..hmmmm