How to determine number of stones for a halo?

[Glassgirl]

I have an 11.59 mm round sunstone that I want have made into a ring with a 2mm stone halo. Can anyone help me figure out how many stones I’ll likely need? I’ve been looking at rings and counting stones, lol. I know I could just send it off to my jeweler and have him mock something up for me but I’m eager to grab some melee from Yvonne Raley if she has enough in stock.

 

[maryjane04]

I can try and help! So based on the size of the round sunshine, the circumference is roughly 36.44mm so you would need roughly 18 maybe 19 just to be safe x 2mm melee.

Hopefully someone else can chime in on my maths skills

 

[Autumn in New England]

@maryjane04's math is spot on, and 18-19 stones is correct. I also physically map it out on my computer, which has never failed me. When I do that, just for kicks, I'm getting 17 stones.

 

[maryjane04]

@Autumn in New England you could definitely get away with maybe 17 stones considering there are probably prongs etc in between so there may be a gap all around of a few mm depending on the setting you choose and how closely the melee are together.

 

[Autumn in New England]

@Autumn in New England you could definitely get away with maybe 17 stones considering there are probably prongs etc in between so there may be a gap all around of a few mm depending on the setting you choose and how closely the melee are together.

Yes, it so hard to account for those things when planning! But better to have a spare or two when in doubt.

 

[Starstruck8]

@Autumn in New England Long time no see! Welcome back!

On topic: To be really geeky, assuming touching circles, and with the halo stones outside the main stone, the formula is:
#halo stones = pi / asin (r2 / (r1 + r2)),
where r1 and r2 are the radii of the main stone and the halo stones. (If this is not obvious, sketch a diagram with just 2 touching halo stones outside the main stone.) This works out to 21.3 by my calcs. So 21- 22 stones.

This is a bit more than the 17-18-19 stones mentioned above. But you have to allow for prongs and spacing, and for the halo stones not being perfectly round. I'd have much more confidence in @Autumn in New England and her computer, and her experience. I'm guessing that her drawing has a realistic bit of leeway in the spacing.

Another issue is symmetry. If you want the halo stones to line up top and bottom, you will need an even number. If you want the same alignment top-bottom and left-right, you will need a multiple of four. This may not matter to you.

This is the sort of thing that jewellers know much more about than I do, so usually I'd leave to them. Or just buy a couple more to be safe.

 

[elle_71125]

This thread has me feeling really embarrassed about my lackluster math skills. Lol.

But at least I know I can come to you ladies next time I need help with something like this.

 

[Rfisher]

I did a dot on grid mock-up and got 21 as well.

How the metal is designed will have some say in how many is needed as well.
You could bump out the radius with a bezel /faux bezel and easily squeeze in 22 for an even number.

Since you are thinking of sourcing the melee yourself - get a few extra to allow for a jumper, a chip, or a replacement down the road.

Yvonne usually is receptive about selecting the most matching pieces, if you ask, and if she’s got the stock to choose from.

Matching for a replacement at a later time might be a pain or nearly impossible.

 

[chrono]

Always get a few extra melees to allow for replacement stones should a few get damaged in the future (for matching size and colour). I think I have 12 to 18 extra Pariaba melees as insurance for my ring.

 

[PrecisionGem]

This thread has me feeling really embarrassed about my lackluster math skills. Lol.

But at least I know I can come to you ladies next time I need help with something like this.

Diameter x π = Circumference (π = 3.1415926)

 

[elle_71125]

Diameter x π = Circumference (π = 3.1415926)

I think I need to go back to school.

 

[Glassgirl]

Thanks, everyone! I was looking at some aquamarine but she didn’t have enough. I ended up finding four oval Paraiba that I’m going to use in a compass style setting. The center stone is so fiery, it’s hard to capture in a photo, but I think glowy paraiba is going to pair well with it. So that’s going to change things up a bit, I’ll probably fill in with diamonds. This is going to get addictive, isn’t it?

 

[Rfisher]

This is going to get addictive, isn’t it?

Yup

 

[Catmom]

This thread has me feeling really embarrassed about my lackluster math skills. Lol.

But at least I know I can come to you ladies next time I need help with something like this.

Me too!

 

[Autumn in New England]

Hey there, @Starstruck8! Thank you for the welcome back!! I hope you've been well.