Its borderline, depending on angle rounding and some other factors it could show leakage or it could be fine. An Idealscope image is needed to be able to tell.Date: 11/23/2009 5:51:49 AM
Author:happy_79
Hi,
Is this stone considered deep steep?
Crown angle: 35.5 degree
Pavillion angle: 40.8 degree
Grader: GIA
Many thanks!
Just because GIA graded it excellent, doesn't mean that it's excellent to everyone's eyes.Date: 11/23/2009 6:18:50 AM
Author: happy_79
GIA graded the cut, polish and symmetry to be Excellent for all... is this worth buying then?
Ditto FB.Date: 11/23/2009 6:20:35 AM
Author: FB.
Just because GIA graded it excellent, doesn''t mean that it''s excellent to everyone''s eyes.Date: 11/23/2009 6:18:50 AM
Author: happy_79
GIA graded the cut, polish and symmetry to be Excellent for all... is this worth buying then?
Without images or a personal inspection, I would not buy that stone because it''s proportions sit right on a borderline and it could go either way.
Again images are needed to properly judge this diamond. Even longer lower girdle facets won't save it if the angles are not tight and swinging out all over the place, sorry but its only guessing as to whether this diamond will show leakage or not.Date: 11/23/2009 7:20:50 AM
Author: happy_79
this is the exact proportion:
ROUND BRILLIANT
Measurements: 5.89 - 5.90 x 3.65 mm
Carat Weight: 0.78 carat
Color Grade: D
Clarity Grade: VS2
Cut Grade: Excellent
PROPORTIONS:
Depth: 61.9%
Table: 57%
Crown Angle: 35.5°
Crown Height: 15.5%
Pavilion Angle: 40.8°
Pavilion Depth: 43.0%
Star length: 50%
Lower Half: 80%
Girdle: Medium, Faceted (3.5%)
Culet: None
FINISH:
Polish: Excellent
Symmetry: Excellent
Fluorescence: Faint
CLARITY CHARACTERISTICS:
Crystal, Needle
i think the people on this site have a strong bias towards high quality cuts. and why not, it is by far the most important determinant of performance? having said that, at the end of the day, a cut is still just one factor. another major factor - cost. not everyone on this site may be able to afford an AGS000. and to be honest, not everyone may want one. even HCA says "worth buying if the price is right." i mean, everyone would want an H&A AGS000 stone if it was the same price as an average stone, but its not - it''s a lot more.Date: 11/23/2009 6:18:50 AM
Author: happy_79
GIA graded the cut, polish and symmetry to be Excellent for all... is this worth buying then?
Date: 11/23/2009 6:37:08 AM
Author: happy_79
But how is deep/steep visible to a layman eyes pls? if i have seen the stone n it looks bright, and sparkly, is it a well cut stone? how can i tell from naked eye that its deep/steep?
Like this:Date: 11/23/2009 9:53:21 AM
Author: Stone-cold11
Narrower facets are the pavilion main facets, they will go black when you look at it within 14inch from the stone, at least the well cut ones do.
If the ring of darkness is not at the edge of the table, but in the center then that is just normal table reflection. Ring of darkness is when you can look through the pavilion. Try using a red/blue color blackground beneath the pavilion to differentiate light leakage from the shadow due to you.
what about steep/shallow? i saw a 37/40.0 stone with 57 table that had fire coming out of the stars/bezel like crazy. but it had an absolutely dead center under the table. was i just seeing things or does the math work out such that those dimensions would have a dark center as well?Date: 11/23/2009 10:01:50 AM
Author: FB.
Shallower pavilions tend have dark arrows against a light background, which can make the stone appear dark in the middle.
Steeper pavilions have light arrows agasint a dark background, which can make the stone apear dark in the middle.
Something in between is ideal - 34.5/40.8, 35.0/40.6, 34.0/41.0 is a good balance. You can push to 35.0/41.0 and still only barely notice the effect of steep/deep. But go to 35.0/41.2 or 35.5/41.0 and it will be obvious.
Slightly steep/deep seem to perform OK. I have one myself.
Severe steep/deep have impaired sparkle from the middle of the stone.
Around 300 people, most in the trade, made 70,000 observations. "For whatever reason" may be attributable to the large obstruction metric (larger than AGSL's avg modeling by about 10 degrees). It explains the GIA metric's center, which favors steep/deep to shallow.Date: 11/23/2009 9:10:53 AM
Author: FB.
The GIA cut grading system was largely determined by getting a large number of people to view a large number of stones.
However, it can be argued that the stones were not mounted and were in a different lighting environment to the average household or office.
But the fact remains that -for whatever reason- some people preferred steep/deep.
In real life viewing the appearance of the pavilion mains depends on the lighting conditions as well as the specific diamond. And diamonds are dynamic. Those "arrows" seen in magnified static images are tiny and will be flashing on-off, broken up by virtual facet-patterns in real life. Even when held still, lighting and viewer position influence how even the most symmetrical patterns appear. I'd mention also that the average level of cut quality doesn't produce crisp even "arrows" as we frequently see them here. Go into a mall store with a H&A viewer or ideal-scope and you'll find that such crisp patterning is a rare animal.I suspect that in a steep/deep, the paler arrows (which seem to be reflective and contrasted against the slight darkness on the table) may have been what some observers found pleasing to the eye.
Certainly, my OH prefers stones that have the less-dark arrows - often found in deeper pavilion stones.
A stone of 40.4/35.0 would have quite prominent and contrasting black arrows.
A stone of 40.7/34 would have medium-intensity black arrows.
A stone with 41.0/33 has arrows that are only slightly contrasted.
It is interesting to note that GIA's excellent grade (determined by real observations) stops at 40.6 pavilion - suggesting a slight dislike of over-contrasted arrows and the steep/deep allows for arrows that are not too prominent.
Then obstruction can be an issue, probably what you noticed by the sound of it. Obstruction can be seen in shallow shallow stones and shallow pavilioned diamonds, normally this is a darkening of the stone due to the viewer's head or body shadow blocking the light when a diamond is inspected closely. Such stones can look bright and sparkly when viewed at a distance.Date: 11/23/2009 10:47:40 AM
Author: rockabee
what about steep/shallow? i saw a 37/40.0 stone with 57 table that had fire coming out of the stars/bezel like crazy. but it had an absolutely dead center under the table. was i just seeing things or does the math work out such that those dimensions would have a dark center as well?Date: 11/23/2009 10:01:50 AM
Author: FB.
Shallower pavilions tend have dark arrows against a light background, which can make the stone appear dark in the middle.
Steeper pavilions have light arrows agasint a dark background, which can make the stone apear dark in the middle.
Something in between is ideal - 34.5/40.8, 35.0/40.6, 34.0/41.0 is a good balance. You can push to 35.0/41.0 and still only barely notice the effect of steep/deep. But go to 35.0/41.2 or 35.5/41.0 and it will be obvious.
Slightly steep/deep seem to perform OK. I have one myself.
Severe steep/deep have impaired sparkle from the middle of the stone.