Back to Ganoksin | FAQ | Contact

3D Gemstone shapes


#1

Hello!

I am new to jewelry design. Working in Adobe Illustrator on a few
designs but get tripped up by my lack of knowledge on the dimensions
of calibrated Does anyone have a book or web reference
containing 3 dimensional gemstone shapes? I’ve found many references
with info on the circumfrence of different cuts but can’t find much
on the heights of different cuts… what the stones look like from a
side view (other than the standard round diamond).Thanks for any
help you can provide.

Lori Fleming


#2
I've found many references with info on the circumfrence of
different cuts but can't find much on the heights of different
cuts... what the stones look like from a side view (other than the
standard round diamond). 

The data that you looking for can be extrapolated from the book by
C.I. Carmona “Gemstone Weight Estimation”. Tables are constructed
based on S.G. of but there are tables of S.G.(s) of most
of the gem material.

Leonid Surpin
www.studioarete.com


#3
Does anyone have a book or web reference containing 3 dimensional
gemstone shapes? 

Well, Lori I recall I had some diamond shapes in 3d, but I believe I
tossed them on a computer change - they were CAD drawings, anyway,
not Illustrator.

BUT - there is much out there on cuts. Calibrated stones are
diamond-cut, so anything about “diamond cuts” will bring up your
info.

Probably more than you want to know:

http://3dbook.octonus.com/dataeng/3dbook.html
http://www.cutstudy.com/cut/

#2 is everything there is about diamond cutting, for most of us.
Click on #14 and you’ll go to a most fascinating animated section,
where you can alter the cuts of diamonds and watch how the light
changes (install a small, harmless app…)

The proportions given on the first link are all you really need to
know…


#4

I have well over 4000 gemstone designs in my libraries and have been
cutting for almost 37 years. On average, most PROPERLY cut gemstones
will display a total depth that is anywhere from about 60% to 75% of
the narrowest diameter of the stone. The great majority will be
around 62 to 70%.

Some custom cuts require a total depth of close to 80% to return
full brilliance for the shape, but I alwyas work pretty closely with
the designer or goldsmith who is making the finished piece so that
they can create the lowest possible setting that will hold the stone
properly.

You will find MANY commercially cut stones with a total depth that
is as shallow as 45% of the narrow diameter, and with crown heights
as low as 10%. No brilliance, or some brilliance around the edge,
otherwise lifeless. And that accounts for about 90% of the sapphire
you see out there today. Sad, really.

Wayne Emery
www.thelittlecameras.com


#5

Perhaps more important than total stone depth will be pavilion depth.
They’re related but by no means consistently so. When you’re plotting
out for the stone the distance from girdle to culet will have more
impact on the dimensions/angles you will need in the finished piece.

Typically I start with the girdle level. If its a suite it becomes
more critical that everything develop from there. Once you determine
your minimum/maximum values you can decide where in that range is the
ideal placement of the stones in regard to the mounting coming up to
meet the stones gracefully.

But it all depends on the mount. Some things will have a bigger
fudge factor.


#6

Lori,

There is a great resource at http://www.3dlapidary.com

He has amassed a huge number of 3D stone models in the DXF file
format. They are 3D wire frame mesh models. You will need some way
of rotating them to get the view angle you want. Most 3D programs can
import DXF. Illustrator CS3 and beyond can import DXF but I don’t
know how it deals with the 3D aspect whether it only gives you a top
view or if there is some way to rotate views. I have CS2 and it will
not i,port DXF so I don’t know about later versions. Programs like
Bryce ($49) will allow you to position, edit and render them for
export as bitmaps but not vectors. Most 3D CAD programs import 3D
DXF and will allow you to modify the files.

James Binnion
James Binnion Metal Arts