CAD help please

[Mrs_Strizzle]

This past July I purchased a gorgeous purple spinel pre loved from the generous @gingercurls that I am finally getting ready to set. I am using a jeweler in Hong Kong that I have used before, but will not be sending the spinel. I will have my local jeweler set it. I sent the dimensions of the stone as well as pics of it and they have sent me the CAD. I would like some other experienced eyes to take a look and let me know if anything should be changed or if you have any ideas to make it even better. It will be all platinum, ring size 5.75. The green stones will be tsavorite.

The one thing that sticks out to me is the depth for the main stone. The spinel measures 7.09mm and 8mm doesn't seem like it's enough. Previously my jeweler has told me he struggled to set another ring I had them made due to this, so it's on my radar. Thoughts, anyone? Thanks!

 

[Rfisher]

Can you show a profile shot of your spinel? Both ways?
It may not just be the all over depth of the stone that’s the issue but the angle/curve of the pavilion from the girdle- and the girdle itself.

Gorgeous spinel is right!

Eta
Also-
If the oval footprint shape of your stone doesn’t match up with what the (generic/calibrated) oval shape the cad user uses, that might also contribute to the setter having more issues.
Along with where you want the girdle to sit compared to the halo, and somewhat how much of overall height measurement of the stone is above the girdle to below it.

 

[Mrs_Strizzle]

Can you show a profile shot of your spinel? Both ways?
It may not just be the all over depth of the stone that’s the issue but the angle/curve of the pavilion from the girdle- and the girdle itself.

Gorgeous spinel is right!

Eta
Also-
If the oval footprint shape of your stone doesn’t match up with what the (generic/calibrated) oval shape the cad user uses, that might also contribute to the setter having more issues.
Along with where you want the girdle to sit compared to the halo, and somewhat how much of overall height measurement of the stone is above the girdle to below it.

Thank you so much for your insight! I did send him one pic of the stone upside down, but not from both angles! It never occurred to me, but now seems so obvious.

So besides the other pic , what do you suggest I say/ask to him to better my chances that it will fit? I understand this would be remedied if I had a jeweler to make it with access to the stone, so I am making it harder on myself using a jeweler so far away and not sending the stone.

 

[Starstruck8]

Beautiful stone and great colour combination. Pairing it with tsavorites is exactly what I'd do. Suffragette colours - is this deliberate? Regardless, the suffragettes had good taste in colour.

The girdle is set unusually high above the halo. I understand why you chose this, because the stone is so deep. But it leaves the girdle - the part most likely to chip - exposed to knocks. Does this worry you?

I don't see the height vs depth, 8mm vs 7.1mm, as a problem. I like to set stones as low as possible (I'm a guy). I'd be happy with about 1mm clearance from the finger.

My jeweller sometimes has CADs made while I still have the stone. They take pictures from different angles - apparently there is a smart program that merges them to a 3-d model. It's worked for me so far. Does your HK jeweller use such a program? If so, have you sent enough good pics? I have to say that for an unusually shaped stone like this, having the setting made remotely seems a bit 'high risk'. Have you shown the CADs to your local jeweller? What does she/he say?

As @Rfisher says, the clearance at the inner edge of the halo could be an issue - either it has to be right as made, or the 'rim' has to be thick enough to allow for filing to fit.

 

[Rfisher]

@Mrs_Strizzle

Do you have the ability for someone with a 3d scanner to scan your stone and then do a 3d print of it?
And in tandem, would the setting vendor be willing/able to build the setting around the 3d printed model you sent to them?
don’t know if this would work - only imagine it might have solved a few issues on a ring I have that is built in similar logistics fashion as what you are planning. A 3d scan itself wasn’t sufficient, but do understand vendors differ.

I know nothing about your stone- so I’m only speaking generically -
If the center stone’s girdle is wavy or the girdle and table facet aren’t parallel to each other - the setting style you’ve chosen /how it’s depicted could make those issues more noticeable once set.

 

[Rfisher]

100% unscientific but it does suggest
that your stone’s belly /pavilion will cause issues, and the stone will probably have to set up even higher than what is depicted in the cad.

My preference (which shouldn’t matter) is that the entire girdle sits just above the edge of the setting. That opening of the center needs to be larger - imo - to achieve that.

 

[dk168]

Personally, if I were to have a setting made without sending the stone to the bench, I would invest on a pair of digital callipers and take a number of measurements of the depth of the stone and send that to the bench.

Callipers are not particularly expensive, easy to buy (plenty listed in Amazon) and well worth the money IMHO for a peace of mind.

I use mine all the time, like measuring the dimensions of jewellery items like the posts of my tiny huggies earrings, and the diameter and depth of my diamond studs etc...

DK

 

[Mrs_Strizzle]

Thanks you so much @Rfisher and @Starstruck8 for your input! You are definitely helping me dive deeper in what to discuss with my CAD jeweler. I know the deep belly of this stone complicates and I do want to get it right.

@dk168 great idea about the calipers with multiple measurements! I actually have some with dead batteries I should find and give to the jeweler.

 

[Dreamer_D]

Yvonne Raley often says in her blog that when making rings for colored stones the prongs need to be cast extra long to allow the setter to account for the often thicker girdles and higher crowns on colored gems. So I would ask them to make the prongs double the length they usually do on the casting. That’s what Yvonne Raley’s casts look like.

To let them set the girdle close tot the halo rather than way above, I’d likely ask them to raise the halo about half a mm. EDIT: and it looks like the opening in the halo might need to be larger as well to allow the gem to sit down into it more.

 

[Dreamer_D]

This video shows the very long prongs that she casts on her mounts.