Tuesday, September 18, 2007

Tourmaline and Purple Gold Lamination

Website http://www.meevis.com

This technical blog assumes you are familiar with faceting and the techniques associated with that discipline. And question can be sent to hans@meevis.com

I still had some purple gold that I bought from http://www.mintek.co.za/ and since I faceted the other piece in the faceted purple gold blog, I thought that I will laminate a sandwich of two tourmaline pieces with a piece of purple gold in the middle and then facet them.

In the picture above I have taken two pieces of different colored Afgan tourmaline and cut and polished one face on each. When I say different colour, I mean that they come out of the same parcel but the are "off cuts". Stuff I would not normally bother with to cut into a faceted stone. I also dopped and cut a perfectly flat piece of purple gold for the center part. This I did not polish, thinking at the time that the glue would have a better surface to grip on. I now don't think that matters, so the next ones I will polish, and so get the added optical advantage of the reflection.

This is the glue I use. It is used to glue the glass of museum cases together. It has to be weighed out accurately hence the carat scale. Oh yes, it also takes 5 DAYS to harden....

So above is a picture of the three busy being aligned and glued.
I used a small 'G' clamp to hold them in place, with only minimal pressure. The masking tape is on the jaws of the clamp so that you can remove the pieces easily---after 5 days...

Glue has hardened, ready for pre- forming

This is done on my Imahshi gem cutting machine.
The piece is then dopped normally and faceted

Like this. (although that is not the actual stone discussed in this blog)

This is the stone being transferred. I used glue on glue, no wax This will be the subject of a future tech blog.

After cutting and polishing the crown the stone is finished.

Here is the stone finished. This was simply a test project. The right side of the stone, cracks are visible. These started as I was cutting the pavilion, as Murphy's law would have it (grin).

This is the pavilion of the stone. The purple gold looks like it does not have crisp corners, but it does.
A few notes.
Rough cutting was done on a worn Crystalite 260 lap
Middle cutting was done on a 1200 lap
Pre polish was done on a copper lap with a 3000 grit.
Polish was done on a Batt Lap and 50,000 diamond powder.
Lap speed was about 1000rpm.
I was worried that the purple gold would interfere with the the polish of the tourmaline, and indeed that did happen occasionally, leaving a 'cat whisker' across the surface. Just a slight change of direction and the problem solved itself.

Prior to this experiment I also test cut a stone that consisted of Peridot and Garnet glued together with the same glue. Again, I did not use the best of material since the potential of failure was good.

And in a manner it was. Not from the physical aspect, rather from the visual.
As you can see, the garnet completely overwhelms the peridot. Hmmmm, next time I will be more cautious with my choice of material. Although it does leave the option of say laminating a yellow and blue stone. I an sure there would be green tone or flashes. As you can see in the picture the reflection has a orange hue, rather than the deep red of the actual colour of the garnet, like the picture below.


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