Do sphene cabochons do dispersion?

[beaujolais]

Do sphene cabochons do dispersion?

Just wondering. Thanks.

 

[T L]

I don't think so. In fact, I have no idea why anyone would cut a sphene as a cab and not take advantage of all that wonderful fire.

 

[Indylady]

Ditto TL, esp. because they are fairly soft as well.

 

[Lady_Disdain]

I don't think so. In fact, I have no idea why anyone would cut a sphene as a cab and not take advantage of all that wonderful fire.

Yep - sphene, sphaelerite and demantoid cabs make little sense to me, even if the colours are nice. Even an included gem will show the great dispersion, while a cab won't.

 

[LD]

Interestingly I don't think I've ever seen one - or if I have, I haven't recognised it! Have you seen one?

I agree though, it would be a horrible loss of dispersion and not sure why anybody would cut one like that!

 

[ruffysdad]

I doubt you'd see much, if any, fire from a cabbed sphene. Dispersion is a function of how the light is reflected back out of a cut stone and how it reacts to the prisms created by the crown facets. That's why I cut a lot of stones with high tables, to enhance the dispersion. Cabs are more of "show the color" thing and the flattened bottom is not designed to enhance light return.

I too can't see a reason to cab a piece of sphene. The nature of most cab settings would leave it too exposed to damage and if you designed a setting that would protect it, then I'd imagine that the light entering the stone would be so minimized that is would overly darken the appearance.

Pete

 

[beaujolais]

Thanks all.

Also, thanks Ruffysdad for doing high crowns - love them.

I've come across some sphene cabs lately and was wondering about them. I'm a sphene lover so had to find out more about these.

Tx again.

 

[ooo~Shiney!]

Thanks all.

Also, thanks Ruffysdad for doing high crowns - love them.

I've come across some sphene cabs lately and was wondering about them. I'm a sphene lover so had to find out more about these.

Tx again.

If you love the Sphene and want a small cab for your collection, why not?

 

[Largosmom]

I would consider a cabbed stone if the color was something I liked. Certainly, I love sphene for its dispersion when it's faceted, but I can say that about many stones. Cabs have a personality all their own.

I will say that the yellowish green that I see in many sphenes isn't the color I would be looking for, however! It does also come in brownish greens, yellows, and sometimes in a granny apple green, so if I liked those colors and the price is right, why not?

The points made about its softness should be considered however. If you set such a stone, you may wish to use it in a pendant, or earrings if you have more than one stone.

Laura

 

[T L]

If you like the color, get a cab chrysoberyl if you can find it. A lot more durable.

 

[beaujolais]

Not so much for the color, TL, just to be more familiar with those dear sphenes. I was thinking they might do something like play-of-color but it seems not.

I hear you all on the hardness. Thanks for the reminder.

I tend to be a bit of an econo-shopper, at times, so it would probably be an e-bay econo-cab. Thanks Oooo & Largo - I do love enablers.

 

[chrono]

I have not seen any cabochons show any dispersion because it is a function of the cut. This is why I held off the sphaelerite cabochon recently offered by Brad. It was a gorgeous colour and wearable as a pendant but seemed a shame to kill the dispersion by not having it faceted.

 

[ruffysdad]

If you can find a cabachon that's clean, you can always have it faceted. Cabs make great preforms if you can get them for a reasonable price but you have to factor in the cost of re-cutting and how much of the stone will go down the drain during the re-cut.

Pete

 

[LD]

Out of curiosity I did an internet search to see what a cab'd Sphene looked like. Most seemed to be quite flat and lacking in dispersion (in the photos) and moderately to heavily included. I was also surprised at how green some looked. Others were muddy looking.

If you do get one, I'd love to know how it performs. As a Sphene lover I'm intrigued now!

 

[beaujolais]

Will do, LD.