Can we generalize?
m4816k
1. Complex, brilliant cuts and their variations serve to make the best use
of good optical properties of gems such as diamond, zircon, garnet etc.(with
the exception of pastel toned, since I heard brilliance can wash out the
more subtle colors), and that their use with "low RI" gems such as quartz,
makes little or no sense?
2. Does the opposite rule also stand - that gems without much brilliance are
best done in "simpler" cuts such as baguette, emerald, cabochon etc.,
especially if poor clarity and/or rich color are present?
3. Size of a stone should be taken into consideration when choosing cut,
since some say that brilliant cut has too many facets for stones smaller
than 0.3, and lacks complexity with stones larger than 1 ct.?
Carl 1 Lucky Texan
So much depends on the individual stone, starting with its shape in the
rough, value, inclusions if any and optical properties that it would be
hard to generalize. I once attempted to make a flow chart to assist
beginning/intermediate faceters in choosing gem cuts. It started with a
nomograph and proceeded from there, there were so many variables! And
intended use of the gem even comes into play. A stone with some easy
cleavages that was large enough for cabinet display MIGHT be carefully
cut with sharp corners (a triangle) but might not survive long in
jewelry. Dark stones (many garnets) might purposely be cut with pavilion
angles allowing 'windowing' to better show the color OR they might be
cut with a very complex crown for the 'scintillation' from the surface
since little light can be refracted out from its interior. Lower RI
material can look quite good - if proper angles are used for pavilion
facets. This becomes problematic for setters as the stone will be quite
deep. Sometimes maximum brilliance might be sacrificed if a material has
high dispersion - higher crown angles can intensify 'fire' from that
material. Birefringent material maigh be cut off axis for higher yield,
but with a simpler pavilion to help avoid 'fuzziness'. Bi-colored
material like ametrine needs very simple cuts, particularly on the
pavilion, UNLESS you make the artistic decision to try to 'mix' the
colors. I've seen very beutiful ametrines cut that way. Of course,
excellent looking stones can be cut violating many of these 'rules' -
but often the stone could be a little better. maybe only 5% or 10% but
better. Foreign cutters have an incentive to maximize weight and speed,
sometimes at the expense of accuracy and brilliance. Still, it helps
make a lot of stones affordable. I cut primarily for myself and my
family. I can't compete with overseas cutters on price - I'm too slow
and often have to pay more than they would for rough material. So, I
make heirlooms.
Do you facet? If not, many Gem & Mineral clubs have classes. A very bold
person might even use 2-3 books and a video tape and teach themselves.
Carl
1 Lucky Texan
--
to reply, change ( .not) to ( .net)
Al Balmer
<marijan.kovacevic@REMOVE_THISos.t-com.hr> wrote:
>Can we say that:
>
>1. Complex, brilliant cuts and their variations serve to make the best use
>of good optical properties of gems such as diamond, zircon, garnet etc.(with
>the exception of pastel toned, since I heard brilliance can wash out the
>more subtle colors), and that their use with "low RI" gems such as quartz,
>makes little or no sense?
>2. Does the opposite rule also stand - that gems without much brilliance are
>best done in "simpler" cuts such as baguette, emerald, cabochon etc.,
>especially if poor clarity and/or rich color are present?
I don't think you can generalize. The cut has more to do with the
brilliance and dispersion than the material, given normal ranges of
color saturation. See Jeff Graham's series of "Mirage" designs, for
example.
>3. Size of a stone should be taken into consideration when choosing cut,
>since some say that brilliant cut has too many facets for stones smaller
>than 0.3, and lacks complexity with stones larger than 1 ct.?
>
Size is certainly a consideration, especially for custom cut stones.
It's probably safe to generalize that small stones should be less
complex, but there are exceptions to every rule.
I think custom faceters rarely cut very small stones, except just for
fun and challenge, since it's cheaper to buy machine-cut or native
cut.
--
Al Balmer
Sun City, AZ
m4816k
"Carl 1 Lucky Texan" <alck...@swbell.not> wrote in message
news:iigm229hdng4k4m07...@4ax.com...
Do you facet? If not, many Gem & Mineral clubs have classes. A very bold
person might even use 2-3 books and a video tape and teach themselves.
- no, I'm just fascinated with gemstones and have interest in learning
about them. I'm not a very handy person, so never tried faceting and also
heard that it takes a quite high initial expense to start faceting
(investing in tools and machines) so never really went for it. I'm just one
of those who like to know a bit more about gemstones than an average person
(that's also why I might post very strange and confusing questions to this
group:). Thanks for answers, it was just that "brilliant cut is initially
designed for diamond, as emerald cut for emeralds", that got me thinking.
M
Carl 1 Lucky Texan
sorry, other post got away before completing my thoughts. Another site
that is more faceting related is http://www.gemcutters.org/ . I started
with a used $300 machine and, of course, upgraded from there. It IS
possible to spend several thousand getting set up, but not required. My
club also has some 'loaner' machines if someone wanted to learn without
a huge investment. You may be able to locate a local club through,
http://www.amfed.org/region.htm ans see if there are any demonstrations
or classes ever in your area. It's an interesting hobby which can be
pursued in different directions, gemology, cut design, collecting your
own rough material, equipment building, competition cutting, etc.
another nice link is ; http://www.rockhounds.com/ with multiple sections
including faceting.
Carl 1 Lucky Texan
There are many good resources on the 'Net' and you can ask away here of
course. A couple of nice gemstone and gemology related sites are
www.yourgemologist.com and www.gemsociety.org .