Questions about RECUTTING.

[blithesome71]

Hi guys, me again. I just made this thread to find some answers to my question re gem recutting.

1. Is it possible to recut a Pear shaped gem to Round brilliant (let''s say the gem dimension is 16x12x9mm,VS-SI Clarity)? Even if the material is normally included like Rubellite, Emerald etc.?

2. For an oval, native cut gem with dimension of 12.5x10x5.7 mm (VS-SI), is it possible to close out its large window but still retain its face up size or does trimming it down to let''s say, 8.5x9mm, necessary?

Hope to get some helpful advise, thoughts, feedback, etc from you guys. Thanks in advance!

 

[T L]

Date: 4/1/2010 10:43:01 PM
Author:blithesome71
Hi guys, me again. I just made this thread to find some answers to my question re gem recutting.


1. Is it possible to recut a Pear shaped gem to Round brilliant (let''s say the gem dimension is 16x12x9mm,VS-SI Clarity)? Even if the material is normally included like Rubellite, Emerald etc.?


2. For an oval, native cut gem with dimension of 12.5x10x5.7 mm (VS-SI), is it possible to close out its large window but still retain its face up size or does trimming it down to let''s say, 8.5x9mm, necessary?


Hope to get some helpful advise, thoughts, feedback, etc from you guys. Thanks in advance!

I think the gem, if it''s included, would have to be evaluated in person. I hope a lapidary chimes in on your thread. Did you ask Jerry?

 

[blithesome71]

Wow, TL, swift response

Nope, I haven''t asked Jerry yet. I saw these two native cut stones (one oval & the other is pear shape) and I''m choosing which one to purchase and is a good candidate for recut. Both are included (esp.the pear) but the oval has a huge window & shallow pav but cleaner than the pear one.

 

[T L]

Date: 4/1/2010 10:54:42 PM
Author: blithesome71
Wow, TL, swift response

Nope, I haven''t asked Jerry yet. I saw these two native cut stones (one oval & the other is pear shape) and I''m choosing which one to purchase and is a good candidate for recut. Both are included (esp.the pear) but the oval has a huge window & shallow pav but cleaner than the pear one.

I know that more weight is typically lost with a shallow cut gem on a recut. I always look for bottom heavy gems for recuts. I just bought such a stone, and I might have Jerry recut it. Also it''s important to take into account loss of saturation of color if there is too much recut. Even a small recut can affect color.

 

[lelser]

Date: 4/1/2010 10:43:01 PM
Author:blithesome71
Hi guys, me again. I just made this thread to find some answers to my question re gem recutting.


1. Is it possible to recut a Pear shaped gem to Round brilliant (let''s say the gem dimension is 16x12x9mm,VS-SI Clarity)? Even if the material is normally included like Rubellite, Emerald etc.?


2. For an oval, native cut gem with dimension of 12.5x10x5.7 mm (VS-SI), is it possible to close out its large window but still retain its face up size or does trimming it down to let''s say, 8.5x9mm, necessary?


Hope to get some helpful advise, thoughts, feedback, etc from you guys. Thanks in advance!

It is possible to recut a pear into a round, but the weight will go down quite a bit. If it has inclusions as a pear shape, the odds are excellent it will have inclusions as a round

For the oval, the answer is "sometimes." If the rest of the cut is nice, and it''s bellied rather than too shallow it can work to just recut the pavillion and keep the face-up size. This sounds to me a bit shallow for that.

With light stones, I like cuts which enhance the colour. They take more depth so you''ll lose face-up but it comes down to a trade off between size and looks. With my own material I opt for looks.

Although I cut for a living, I do recuts only for my own inventory. I don''t recut for others.

Cheers,

Lisa

 

[Michael_E]

Date: 4/1/2010 10:43:01 PM
Author:blithesome71
Hi guys, me again. I just made this thread to find some answers to my question re gem recutting.


1. Is it possible to recut a Pear shaped gem to Round brilliant (let''s say the gem dimension is 16x12x9mm,VS-SI Clarity)? Even if the material is normally included like Rubellite, Emerald etc.?

Inclusions have nothing to do with recutting unless they are located in an area which could potentially be removed during recutting. If the inclusions in the pear are in the tip, then they could be removed, leaving you with a much cleaner and brighter stone. The other thing to consider in recutting from one shape to another is the "aspect ratio", (length/width of the stone before and after. A long skinny pear, (with a high aspect ratio), will cut a much smaller round, (with an aspect ratio of 1), than a short fat pear, (a smaller aspect ratio), and you would probably lose less material in cutting either shape to an oval or better yet a shorter pear. Always try to keep a recut in a similar aspect ratio if not a similar shape.

. For an oval, native cut gem with dimension of 12.5x10x5.7 mm (VS-SI), is it possible to close out its large window but still retain its face up size or does trimming it down to let''s say, 8.5x9mm, necessary?

The depth ratio of most colored gems should be at least 60% or above. Since 5.7 divided by 10 is 57% this stone is a little short to be recut without making at least the width smaller. If the pavilion is tall and the crown is short it may be improved and the window removed, but short crowns, limit what can be done to reduce the size of the tilt windowing that all stones will show at relatively low tilt angles. On a stone with these dimensions I would recommend a total recut to maybe 11 x 9...which is a calibrated size and gives you a lot of options for using calibrated settings with a substantial cost benefit over custom settings.

 

[mastercutgems]

Blithesome71;

As far as re-cutting; the group is correct inclusions will not really play a part unless they are fractures, veils, etc. that will even further get in the way of the optical properties of the gem with the new finished cut.

#1 I would say will create a nice 11mm brilliant cut round per the dimensions given from the original pear shape; maybe a little more but a 11 should work fine.

#2 on the oval you could maybe get a 10 x 8 mm oval or just a shade under although it will more-than-likely be a keel culet instead of a brilliant point culet...

Of course all this is guesstimating as the gem has not been seen to give a proper evaluation. I just use the normal rule of 75% depth to width ratio to be sure you will get a brilliant gem with proper crown height... old school

I do know if it is light enough material even though it has some inclusions the gem will glow more than with a window.

I hope that has helped...

Most respectfully;

 

[blithesome71]

Guys thank you so much for all your helpful response most esp. to the respected gem cutters who chimed in. I was really torn because both have inclusions & so I thought inclusions might affect the recutting process. I attached here some photos of the Pear gem I''m considering. However, will the visible inclusions affect its overall looks after it''s been recut? Or (hopefully) not? Here:

 

[Pandora II]

Is there a reason why you want to buy a stone and then have it recut?

Why not just work with a vendor to find the stone you want that way. By buying a stone to recut you will have the problems of trying to find a cutter prepared to do this, any issues the original material may throw up, a lot of added expense and potentially an end result that is not what you are after.

ETA: The photos you have posted show typical inclusions for spessartite garnet. Recutting this particular stone will not get rid of the inclusions. Spessartite is relatively easy to find in clean pieces so I wouldn't go with this one.

 

[chrono]

With all those inclusiona scattered throughout the stone, I’m not sure if any cutter will take the risk of touching it. It’s probably better to look for another stone that meets your requirements.

 

[blithesome71]

Thanks chrono & pandora.

I guess I''ll just pass on this stone and will go for the oval instead (hopefully it''s still available)... Btw, it''s not a spess. I only got interested on this one due to its size and fair rarity (I own one but it''s only 1.04ct!). 11ct Clinohumite from Tajikistan.

Later*

 

[gsellis]

With that pear, the deepest part of the stone that would save the most mass will center that line of inclusion going to a round. You might get 5 cts, but that might be a tad optimistic. And that new stone would have a line centered on the table.

If you do go forward, as included as it is, even a pear recut may not improve the performance too much. But it does look like orange marmalade. It needs pieces of toast on either side. Kind of cool.

Edit - btw, the more interest stone with less inclusions would be using the tip and cutting a triagular form. It would be rather small though.