crown heights/angles on ECs Q ??

[shminbabe]

i read something in a past thread that talked about the best stats for a great cut EC. The poster wrote that the ''crown angle'' should be 32 - 36 degrees. How is this different from ''crown height''? On the chart for cut classes it indicates that the ''best'' crown height is between 12 - 15 %.

I was told that the EC I''m looking at has a crown height of 13. 7 and on the Sarin report it says the ''crown angle'' is 26.3 degrees.

I have NO idea how to interpret this information. So, while on on the one had the stone I''ll be considering has a "great" crown height at 13.7%, its crown angle at 26.3 degrees is way out of the ideal range of 32 - 36 degrees.

Is this right? How does one interpret this information? Should I not call in the stone b/c of this? Every other stat seems really good...i''m just hesitant if one important factor is out of whack.

help me, please!

jeannie

 

[pyramid]

Maybe a large table is make the crown angle lower.

 

[diagem]

Date: 7/16/2007 2:29:55 AM
Author:shminbabe
i read something in a past thread that talked about the best stats for a great cut EC. The poster wrote that the ''crown angle'' should be 32 - 36 degrees. How is this different from ''crown height''? On the chart for cut classes it indicates that the ''best'' crown height is between 12 - 15 %.
Degrees= angle of facets
Crown height= distance between girdle plane and table facet.
I personaly prefer higher crown height..., but that is just me!

I was told that the EC I''m looking at has a crown height of 13. 7 and on the Sarin report it says the ''crown angle'' is 26.3 degrees.

I have NO idea how to interpret this information. So, while on on the one had the stone I''ll be considering has a ''great'' crown height at 13.7%, its crown angle at 26.3 degrees is way out of the ideal range of 32 - 36 degrees.
The crown facets of an E/C are usually made of three different steps..., if i am not mistaken..., the sarin reads the step-facet closest to the table (which is the shallower facet out of the three), now the rest depends on the angles of the remaining two...


Is this right? How does one interpret this information? Should I not call in the stone b/c of this? Every other stat seems really good...i''m just hesitant if one important factor is out of whack.
Can you post an image?

help me, please!

jeannie

 

[shminbabe]

I don''t haven an image yet b/c I haven''t given the final go-ahead to call this stone in. I''m so confused; the more I read the the less I know. I really appreciate your answers; it''s all so unclear to me. I must sound like a total moron. I''m trying to follow the "specs" on this ''cut classes'' chart i printed from price scope which suggests the ''best'' cuts based on percentages of table, depth, crown height, girdle thickness, and so on. I am sure you are familiar with it. In trying to pick the best EC stone I can but doing it online, relying upon the skill of all you nice pricescopers, plus the (sales) guy at whiteflash, with every other jeweler in town deriding my notion of purchasing a quality stone online, reading all the back threads on ECs, posting my dumb questions, getting your very nice answers that I don''t fully understand, truth be told. I guess I''m really tired and stressed out over this.

I''m fortunate to be stressed out b/c I am lucky enough to be purchasing a large diamond. Another person I know who is younger than me and has two little daughters to miss is dying in a hospice tonight.

sigh.

jeannie

 

[strmrdr]

Sorry to hear about your friend, prayers are outgoing for her and her family.


different scanners reports state the crown angle in different ways for EC''s not knowing what scanner it was makes it impossible to say anything about the angle.
13.7% is puuurfect with the right table size ignore the angle.

 

[diagem]

Date: 7/16/2007 4:14:07 AM
Author: strmrdr
Sorry to hear about your friend, prayers are outgoing for her and her family.


different scanners reports state the crown angle in different ways for EC''s not knowing what scanner it was makes it impossible to say anything about the angle.
13.7% is puuurfect with the right table size ignore the angle.

Strmrdr,

Do I understand correctly...
The angles of the crown step-facetS on a E/C (or any step-cut Diamond) is ignorable as long as you have the right CA and CH?

 

[strmrdr]

Date: 7/16/2007 4:50:08 AM
Author: DiaGem

Date: 7/16/2007 4:14:07 AM
Author: strmrdr
Sorry to hear about your friend, prayers are outgoing for her and her family.


different scanners reports state the crown angle in different ways for EC''s not knowing what scanner it was makes it impossible to say anything about the angle.
13.7% is puuurfect with the right table size ignore the angle.

Strmrdr,

Do I understand correctly...
The angles of the crown step-facetS on a E/C (or any step-cut Diamond) is ignorable as long as you have the right CA and CH?

If you know the table% and crown height and you can get good pictures and preferably an aset image the angles are pretty useless info.
You could calculate the average crown angle if you really wanted too from that.

Also unless you run the stone on a helium scanner the angles reported are going to be off anyway but that''s another story....

 

[diagem]

Date: 7/16/2007 4:56:29 AM
Author: strmrdr

Date: 7/16/2007 4:50:08 AM
Author: DiaGem

Date: 7/16/2007 4:14:07 AM
Author: strmrdr
Sorry to hear about your friend, prayers are outgoing for her and her family.


different scanners reports state the crown angle in different ways for EC''s not knowing what scanner it was makes it impossible to say anything about the angle.
13.7% is puuurfect with the right table size ignore the angle.

Strmrdr,

Do I understand correctly...
The angles of the crown step-facetS on a E/C (or any step-cut Diamond) is ignorable as long as you have the right CA and CH?

If you know the table% and crown height and you can get good pictures and preferably an aset image the angles are pretty useless info.
You could calculate the average crown angle if you really wanted too from that.
Average..., but you wont be able to imagine the look or beauty of the Diamond!
And I am not even mentioning the corner-breaks...

Also unless you run the stone on a helium scanner the angles reported are going to be off anyway but that''s another story....

 

[chrono]

Date: 7/16/2007 4:56:29 AM
Author: strmrdr

Date: 7/16/2007 4:50:08 AM
Author: DiaGem

Date: 7/16/2007 4:14:07 AM
Author: strmrdr
Sorry to hear about your friend, prayers are outgoing for her and her family.


different scanners reports state the crown angle in different ways for EC''s not knowing what scanner it was makes it impossible to say anything about the angle.
13.7% is puuurfect with the right table size ignore the angle.

Strmrdr,

Do I understand correctly...
The angles of the crown step-facetS on a E/C (or any step-cut Diamond) is ignorable as long as you have the right CA and CH?

If you know the table% and crown height and you can get good pictures and preferably an aset image the angles are pretty useless info.
You could calculate the average crown angle if you really wanted too from that.

Also unless you run the stone on a helium scanner the angles reported are going to be off anyway but that''s another story....

Jeannie,
All this detailed talk of angles and what not is getting too much into buying the paper and not the stone. I''m with Storm in that if you know the table % and crown height (which you already do and they both look great

), it''s worth calling the stone in to get good pictures and an ASET image.

 

[strmrdr]

Date: 7/16/2007 5:11:26 AM
Author: DiaGem

Date: 7/16/2007 4:56:29 AM
Author: strmrdr

If you know the table% and crown height and you can get good pictures and preferably an aset image the angles are pretty useless info.
You could calculate the average crown angle if you really wanted too from that.
Average..., but you wont be able to imagine the look or beauty of the Diamond!
And I am not even mentioning the corner-breaks...

Also unless you run the stone on a helium scanner the angles reported are going to be off anyway but that''s another story....

Yes, which is why if you cant see it in person you have to get pictures.

 

[shminbabe]

Chrono, Strmrdr, and all:

thanks for your responses. it''s all confusing but you are very reassuring!

yes, i did post the #s last week and the stone looks pretty good.

i''ll be counting on you all to advise me once I "see" it - pics, etc.

THANK YOU! (and thanks for the prayers for my friend. it''s too sad for words and makes all the diamond talk feel very shallow to me, you know?)

jeannie