Open vs Closed Gemstone cut

[treasurehunter]

https://www.youtube.com/watch?v=PfeXYfKudZY

Anyone know what causes the Closed aspect of a gemstone cut - the crown or pavilion angles ?

 

[Michael_E]

Yes. The extremely poor lighting that he was using was causing the darkening effect you see. Nothing else can be guessed about cut when using such poor lighting.

 

[treasurehunter]

I have seen stones though when you look directly under the diamond lamp or light source look amazing but in diffused lighting darken up, the open stones catch light from all angles

 

[chrono]

The light source is definitely poor and the stones are too far away for me to make out anything about the cut.

 

[chrono]

I have seen stones though when you look directly under the diamond lamp or light source look amazing but in diffused lighting darken up, the open stones catch light from all angles

The type of stone that looks great under very strong direct light but darken up under bright diffused light are those that are overly dark in tone.

 

[T L]

https://www.youtube.com/watch?v=PfeXYfKudZY

Anyone know what causes the Closed aspect of a gemstone cut - the crown or pavilion angles ?

It can be many things. I've even seen precision cut gems that looked extinct under some lighting.

It can be stone depth, a deeply cut stone will often be darker than the same material that is cut less deeply.

It could be the material. Extinct material and darker toned material will look more closed than a pastel stone for example.

I think the lesson I would take away from this video is to view a gem in various natural and artificial light sources before making a determination in whether to buy, or not.

 

[minousbijoux]

I'm wondering if he is not attempting to show how a stone with a closed c axis might affect its appearance? Even so, its a poor example and really tells nothing based on the lighting and the distance from the camera.

 

[Justin_Cutter]

I'm wondering if he is not attempting to show how a stone with a closed c axis might affect its appearance? Even so, its a poor example and really tells nothing based on the lighting and the distance from the camera.

I was wondering the same thing!
~Justin