Sapphire Cut

[michelel]

I recently saw a sapphire I liked on the Natural Sapphire Company''s website. It was #b458 and it is very reasonably priced at $410 a carat with the following specs.

Item ID: B458 Description :
Weight ( Ct ): 1.82
Color: Blue
Dimensions(mm): 8.04 X 6.91 X 3.41
Origin: Ceylon
Treatments: No Enhancement
Shape: Oval
Cut: Fancy Brilliant
Color Intensity: Medium Strong
Clarity: Insignificant Inclusions (VVS2)
Per Carat Price: $ 410
Total Price: $ 746.20

The problem is that the picture shows that the stone has a large table and is bottom heavy. It says that it appears larger than its carat weight. I like this sapphire, but I am worried that if I buy it that I won''t be able to have it set. I don''t know much about gemstones. Is it bad to buy a stone with a large table?

Michele

 

[movie zombie]

you may have to have a custom made setting but if you like the stone, go for it. if the 3 is the depth, i don''t think its deep at all.

peace, movie zombie

 

[colormyworld]

Hi Michele, I am not an expert or have I seen the stone but with a depth of less than 50% The stone may have a window. If the color is rich enough it may not be noticable except the window will not return light if there is a window. Regards Doug

 

[valeria101]

For the record... the pictures were still on the seller's website and picked them up.

There seems to be a window (the even colored=not brilliant, patch in the upper half of the stone towards the centre. The color is not dark as described (great!) so the window is not meant/needed to lighten it up. The picture is not strictly face-up with the table parallel to the camera's lens... and the tilt exposes the window at its worse. The setting will somewhat help too.

Anyway, you will surely get to see this and it remains a personal choice if the trade-off size/cut is appealing after all. I would love the color on the computer screen on a sapphire - window or no window. This stone could have probably been a much small sapphire with no window (say, a round or oval about 5-6mm across like this or this ... who knows what shape the depth may have accommodated). The idea of wasting half of the sapphire's weight for that purpose hurts me, let alone the seller. And the price takes that into account, at least relative to other things in the shop.


Just my 0.2. 'Sapphire cut' makes great conversation as far as I am concerned

 

[valeria101]

Oups... forgot the picture:

 

[valeria101]

For what that matters... there is a non-windowed brother of that sapphire on the list. I was looking for an example to illustrate the size/cut tradeoff. And it came up closer than I would have expected. The picture below shows the two sapphires to scale to the best of my abilities. The seller labels colors differently (''intense'' versus ''medium'') which I would not expect the pictures to show well, and I can''t possibly know how these two actually look side by side. Size, shape and the window in the larger piece show well enough, IMO.

Just a thought...

 

[valeria101]

arrrgh...

 

[widget]

OT: Is anyone else having trouble getting onto the NSC site? For two days now I''ve been getting a "default page"...????

widget

 

[valeria101]

Date: 11/22/2005 10:07:16 PM
Author: widget

OT: Is anyone else having trouble getting onto the NSC site? For two days now I''ve been getting a ''default page''...????

Just got into it without problems... after disabling firewall

Something must have changed.

 

[Michael_E]

When you folks are looking at any colored stone and trying to determine the quality of the cut as it relates to a stone that is fully reflective, (no window), when viewed straight into the table, you need to remember just a few things as follows:

1. For reflectivity that that is complete and shows no window, the total depth percentage must be at least 55% and the angles closest to the culet must be above the critical angle of the material. In sapphire this is about 38 degrees or so, minimum. This number is not exact , but if the bottom of the stone looks flat like the bottom of a boat or a flying saucer, then you will have a window.
2. The crown depth to pavilion depth must be well "balanced". This means that the crown should be no more than about 1/2 the depth of the pavilion and preferably closer to 1/3. This can be judged rather easily by looking at a side view and estimating whether the crown looks too tall for a stone that has minimum depth percentage.

Looking at pictures doesn''t really cut it, since the light can be manipulated to show good reflection on 1/2 of the stone, in a shallow cut stone. The first set of pictures here is a good example of a stone that is cut too shallowly and will have a pretty severe window. If the stone in question were cut for it best brilliance it would lose about 1/2 carat of weight and about 1mm in width and another 1/2 mm in length. This would put it''s cost at closer to $600 or $700 per carat, (but with lighter weight, so there''s some offset to the increased cost), but with very much higher brightness.

The choice about how to cut a stone like this depends on how the initial seller and cutter see the piece. Some folks want maximum size and good color in an unheated stone. They may not be particular about the "sparkle" factor. Others are very particular about everything and will pay the additional cost per carat for a smaller, better looking stone. The example that Ana has shown illustrates that quite well, with the better looking stone having nearly the same color as the poorer looking stone, but being described as intense due to the better cutting.