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 Post subject: Orientation and Cutting the Catseye Tourmaline
PostPosted: Sat Mar 15, 2014 6:20 am 
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Joined: Mon Aug 19, 2013 9:50 am
Posts: 24
I don't get to do much research and searching on the Forum & with the Group but I've come across some catseye tourmaline that I purchase from a tailgater last year. Nothing spectacular, just a few small pieces. It was in a small lot of some other gemstones that I purchased.

The plastic bag it was in was labeled star tourmaline. Being the senior citizen that I am I figured that they got me again. Couldn't find much about star tourmaline but this evening I was thinking again and wondered if it might be catseye tourmaline. Some rough pieces do show a catseye.

The question Is, and somebody correct me if I'm mistaken, the catseye appears to be on the outside of the crystal and it is very dark material. I haven't found any catseye phenomena inside the crystal. How deep would the catseye be found?

What would be the suggested orientation & procedure for cutting the stone? Probably cab in this case: would the catseye be on the bottom and the dome on the opposite? Apologize for the length of post but would like to get some of those that are much more knowledgeable in these matters. Your input, suggestions, an assistance would be appreciated. Thank you very much for taking the time to read & post. :) IV


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 Post subject: Re: Orientation and Cutting the Catseye Tourmaline
PostPosted: Sat Mar 15, 2014 11:30 am 
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Joined: Mon Feb 11, 2008 11:11 pm
Posts: 506
Location: Moncton, Canada
Hello Ivanhoe,

The cat's eye effect is caused by fine fibres (open growth channels AFAIK) running along the length of the crystal. Often they are not uniform but concentrated in small areas. I've cut quite a few of these and in fact published a story in "Lapidary Journal" on how to orient the crystals. But that was years ago; I don't remember which issue it was.

Here are some I cut last week - all about 6mm in diameter...

Attachment:
cat'seye-forGO-8016.jpg
cat'seye-forGO-8016.jpg [ 196.65 KiB | Viewed 2430 times ]



To bring out the cat's eye the stone is cut with its base parallel to the length of the crystal - like this

Attachment:
catseye-orient-forGO-8021.jpg
catseye-orient-forGO-8021.jpg [ 96.16 KiB | Viewed 2430 times ]


If the channels are very fine and uniform you might (conceivably) get a star stone cutting at right angles to the above, i.e. with the base of the stone perpendicular to the length of the crystal. But this is speculation, I've not done it.

Cheers
Hans Durstling
Moncton, Canada

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 Post subject: Re: Orientation and Cutting the Catseye Tourmaline
PostPosted: Sat Mar 15, 2014 11:05 pm 
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Joined: Mon Aug 19, 2013 9:50 am
Posts: 24
Hans Durstling wrote:
Hello Ivanhoe,

The cat's eye effect is caused by fine fibres (open growth channels AFAIK) running along the length of the crystal. Often they are not uniform but concentrated in small areas. I've cut quite a few of these and in fact published a story in "Lapidary Journal" on how to orient the crystals. But that was years ago; I don't remember which issue it was.

Here are some I cut last week - all about 6mm in diameter...

Attachment:
cat'seye-forGO-8016.jpg



To bring out the cat's eye the stone is cut with its base parallel to the length of the crystal - like this

Attachment:
catseye-orient-forGO-8021.jpg


If the channels are very fine and uniform you might (conceivably) get a star stone cutting at right angles to the above, i.e. with the base of the stone perpendicular to the length of the crystal. But this is speculation, I've not done it.

Cheers
Hans Durstling
Moncton, Canada


Cheers to you Hans and thank you for your follow-up on the Catseye. It appears that the eye is perpendicular to the C axis. Your catseye cabs, in my opinion, are very nicely done. Thank you for sharing your work an explanation. Not sure if I got this right? By cutting the base parallel to the length of crystal, and I just have a few bits and pieces of crystal, that the catseye will be at right angle to the "c" axis? Hope I got that right?

You mentioned the article you wrote for LJ. Must have a couple of hundred pounds of Lapidary Journal, Rock & Gem. Rock & Minerals, Gems & Minerals, etc. Some go back to the 40's. It's possible I may have your story somewhere but ....... Sorry I'm not better organized.

Feel more comfortable with the information and cabs you posted are outstanding. Again thanks for taking the time to reply. You made my day! :)

Kindest regards,
Pete from Pa.


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