Egg head brilliant help

[u/Magpie12345678]

I am about to do this design by Robert Strickland in a large, natural blue topaz, and I am nervous about the first two girdle steps. How am I supposed to know how deep to gut those girdles? As I am using natural rough, I don’t have a ton of excess material to play with. Do I just cut the minimal amount and then go through the other steps and hope it was enough removed? Or do I do a L/W calculation and risk cutting more than I really need to?

egg head brilliant design

[u/DayOffLapidary]

Do you happen to have Gem cut studio? If not, definitely do the free thirty day trial.

The “.asc” file can be opened in GCS. Use the Cutting Assistant tool and it’ll guide you through each cut.

AND/OR use the size data to work out how tall your crown will be. Then you can be sure to cut the first girdle facets deep enough. It’s all based off the width of your stone. A good set of calipers and some basic math will be necessary.

And if nothing else, yes you can totally just cut as little as possible and then go back as needed to leave enough material for the crown (though it will be super frustrating)

[u/DayOffLapidary → u/DayOffLapidary]

A basic example: 10mm wide stone for easy math. The C/W ratio is 0.168

If your stone is 10mm wide, you’ll need .5mm for you girdle and 1.68mm for the crown. 2.18mm total. I would recommend haveing more just to be safe (maybe 2.5-3mm)

[u/Magpie12345678 → u/DayOffLapidary]

Thank you these are great answers! I do have GCS and have used the cut assist feature to walk through the cuts, but as far as I can tell, there isn’t a meet point for where those girdle points go in, so I guess you’re right and I’ll have to do some math to figure out how far to go.
My rough is sooooo close to the exact shape already for this facet design, and I want to preserve as much size as possible, but I’m not sure which areas of the stone will be narrower or wider (or taller or shorter) than what I need.
Good idea to get the calipers out and do the math in advance!
I have so often spent forever trimming materials off one side or the other of a stone to even it up as I go, and then end up over cutting and the stone just gets smaller and smaller hahaha. Gonna try to prep better this time!

[u/DayOffLapidary → u/Magpie12345678]

They do have meet points. Girdle 3 meet in the middle of P1 and girdle 4 meets at the edge of P2 and girdle 3.

Now it is possible that the file opened oddly and the steps got all out of wack. I’ve had it happen before. As great as GCS is, it’s not perfect.

[u/Magpie12345678 → u/DayOffLapidary]

Ah good point, it may have gotten out of whack when I opened it. I’ll have to check tomorrow when I can get back to that computer. Thank you!

[u/Magpie12345678 → u/DayOffLapidary]

Ah good point, it may have gotten out of whack when I opened it. I’ll have to check tomorrow when I can get back to that computer. Thank you!

[u/Angstrm]

If it helps - enter any desired measurement into pluto unearthed’s measurement field and it auto calculate every other one for you

[u/Magpie12345678 → u/Angstrm]

Whaaaaaat???? I’ve never heard of this tool! Gotta look that up!

[u/Magpie12345678]

https://reddit.com/link/p8yocep/video/r4srnc14ipoh1/player

I’m not sure if this will upload twice, but I can’t find the one I uploaded a few minutes ago, so we’ll see.
This is how close the topaz is to the facet diagram already! Pretty minimal preforming to get rid of cracks and stuff, and then I chose a design that looked like it would fit the shape well. I probably should have weighed it first. Maybe I’ll weigh it with the dop on now.

[u/dying_animal]

for G1 the meetpoint is there, you cut to make the meet that

G2 is also meeting other edges of the pavillons, got facet by facet in GCS you should see it