Cristinite creation

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I'm a big fan of things natural as they came from the earth but a mate gave me a chunk of bi-coloured blue-orange cristinite so I thought I'd give this design a lash - "Cleopatra's eye".

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It's about 11mm long. My gem photography skills are improving but I've still got a ways to go - the "stone" is perfectly polished and without any inclusions (as you would expect man-made stuff to be), it's not easy to take a photo of how a faceted gem looks in real life, the camera often wants to see things wrong that don't actually exist.

I think this design will turn out more useful than I originally thought. You can afford to waste a little bit of man-made stuff that was given to you but you don't want to waste good natural stone just to get a particular shape. But upon examining a lot of quartz crystals that I have (many from Lowmead), a lot of them are not perfectly hexagonal through the cross-section but a are slightly squashed toward the ends - a perfect shape for this design.

I think this would look good in a nice piece of amethyst, perhaps set into an Egyptian-style setting.

What I reckon would look awesome would be this design in a good-sized pharaoh's eye sapphire - so long as the shape of the rough was close enough so as not to waste valuable sapphire.
 
Very Nice Lefty.... I like the way you Add your Own to the Stones.... We will meet at Lowmead soon... now the weather has Cooled a bit... Maybe a PA Meet-up?

LoneWolf....
 
Cheers everyone.

Yeah, I'm starting to branch out into more arty and complex designs. The intriguing thing about this one is the way the light swirls as the stone is turned. I'm wondering now if it has to be that navette shape or if a round with the double barion feature of this design would produce the same effect?

The temperatures are just starting to become more friendly here in CQ - digging season is upon us! :) Still not sure about this weekend but very soon......
 
I like the look of that Lefty, different from the norm hey ! :Y: :cool: :Y:
 
Lefty said:
Cheers everyone.

Yeah, I'm starting to branch out into more arty and complex designs. The intriguing thing about this one is the way the light swirls as the stone is turned. I'm wondering now if it has to be that navette shape or if a round with the double barion feature of this design would produce the same effect?

The temperatures are just starting to become more friendly here in CQ - digging season is upon us! :) Still not sure about this weekend but very soon......

That looks fantastic :Y: :Y: :Y: .I think you have discovered the benefit of synthetics. They are great to play around with and have there place.It's horses for coarses I guess.

A question. How did you orientate the stone? Blue or orange on top?

And yep the photography is looking way better. I think getting a decent pic is close in complexity as cutting the stone.
 
Yes, man-made certainly has it's place. Lots of inexpensive material to experiment with, doesn't matter if you stuff something up while mucking around. This particular stuff has no real natural counterpart but the synthetics such as flame fusion created sapphire are also really good to play with because they behave much the same way as the very much more expensive natural stuff, so you can get some prior experience working with that stone without a costly mishap. I have plenty of natural material to experiment with that didn't cost me anything except fuel and beer (colourless quartz and straw-coloured labrodorite) but it's fun do work with more brightly coloured material.

I did orient it to put the blue and orange on top so it was a bit of a surprise when the finished gem showed a centre that stays blue while the green sort of spins around the outside when it is moved. The green was not visible in the chunk of "rough" from that perspective, you have to look through the end to see the green. I guess the way this design reflects light is responsible for creating the green where it originally looked orange. Here is the Cleopatra's eye faceting diagram.

I gave up trying to use the old digital camera, it just seems to be programmed to hate faceted stones. My wife's iPhone took the above photo. My photography set-up is a cardboard grog box from Dan Murphy's, with the top cut out and a white plastic shopping back slipped over it :) , faceting lamp illuminating through the bag from above.
 
Photos are a bit blurry but here's another bit of the same bi-coloured material, this time in a rectangular barion with a step crown. I knew of the colour-mixing properties of the stuff but I wasn't really expecting a half (or one-third) orange and blue piece of material to turn out the way it did when viewed down on the crown - green on both ends with a bar of blue across the middle.

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Anyone got any ideas why? Is it just the material itself or does a barion-type pavilion add to the effect?
 
Also, just finished another piece of the stuff (just straight orange) in an extremely simple triangular design found in an old lapidary magazine. Haven't photographed it yet. Looks really nice, triangular designs always seem to give the impression in their reflection pattern that the pavilion has more facets than it really does (this design has only six).

Even here, I've found that different individual pieces of the same man-made material can respond differently to polishing. The table of the gem above proved virtually un-polishable with most of the approaches I tried. I eventually got a decent polish on it using #100 000 water-based diamond on a Darkside lap. The triangular piece also had a large and difficult table - but it would not respond to the same approach that had been successful for the previous piece, it just kept on scratching badly. I ended up putting a pretty good polish on it using cerium on a Perspex (which in my experience does not round facet edges anywhere near as much as some people say it does) lap - the exact combination that simply would not work at all for the previous piece.

My experience has been thus far that if you only ever work with one type of material (eg, sapphire) then one single lap and polishing agent may be all you need in nearly all cases. But if you're working with a wide variety of different materials with differing hardnesses and crystal structures then it does pay to have a variety of polishing laps and agents on hand.
 
Anyone got any ideas why? Is it just the material itself or does a barion-type pavilion add to the effect?

If anything Lefty we're all learning heaps about light travel through a stone. Try sticking the design on GemCad not Gem Ray and with the Raytrace option see where the light enters and leaves the stone.
I'm fairly sure that it'll explain it, I was intending to type it but it sounded more like an incoherent ramble.

This is a good example of why steep ends are required on some Tourmaline to avoid the mixing of colours - although that is generally referring to the 'c' axis. But I think if you cut the ends steeper the colour would not mix.....................much.
 
Cheers Heatho. It's not worth anything but it sure looks pretty.

If anything Lefty we're all learning heaps about light travel through a stone. Try sticking the design on GemCad not Gem Ray and with the Raytrace option see where the light enters and leaves the stone.
I'm fairly sure that it'll explain it, I was intending to type it but it sounded more like an incoherent ramble.

This is a good example of why steep ends are required on some Tourmaline to avoid the mixing of colours - although that is generally referring to the 'c' axis. But I think if you cut the ends steeper the colour would not mix.....................much.

I don't actually have either Gemcad or Gemray MM, though I want to get them. Nearly everyone recommends them highly.

The reason I asked is because I cut the same material earlier in a full step cut, both crown and pavilion - the result was a gem that remained half blue and half orange regardless of the viewing angle. I don't think the ends were particularly steep compared to the one above. That made me suspect the barion pavilion might cause light to "swirl" in a way a step pavilion does not.
 
To add to that, I now can't recall that I've seen ametrine cut with a non-step pavilion though admittedly I've only seen a small number of faceted ametrines.
 
Good point. The ametrines are split and stay split. I do have a heap of split Bolivian ametrine, I may have to check this out.
Is there a GEM file for those cuts. I could have a quick look to see if that explains what is going on.

Re GemCad/Ray: Since you have gone this long without it is possibly worth waiting until that Rej(?) has finished off his program. That seems to be getting a rapturous report and it may be worth waiting for.
 

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