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Gemstone Cutting @ Jewel Info 4 U
By:Sheweta Dhanuka
Gemstones in the jewelry items
enhance beauty of the women making
her more attractive and splendid.
Gem makes women beautiful and gem
cutter makes gems beautiful. When
woman is seen wearing the gemstone
jewelries it is in it's finest form
but initially as rough any precious
or semi precious stone is as simple
and pale as a normal pebble. It
achieves it magnificent look after
it undergoes the gemstone
processing. This process is known as
Gem Cutting or Lapidary that
involves cutting and polishing. An
individual performing this art on
the stone is known as gem cutter or
lapidarist.
These amazing gemstones are created
deep under the earth crust by the
grace of Mother Nature. Innumerable
chemical reactions take place in
varied weather conditions like high
temperature, pressure etc and then
stones are retrieved after difficult
mining. The material procured as the
result of mining is referred as
rough. The rough undergoes
gem-cutting process in order to get
transformed into small stones so
that it becomes wearable and useful
for other purpose.
Gem cutting is a long process that
takes many months to convert simple
rough into fascinating gemstone. It
involves many steps. In order to
acquaint the reader with the overall
process of gem cutting, all the
steps are explained one after the
other. The steps elucidated are not
in any fixed sequence. The reason
being, it is not necessary that each
single stone would go through all
the mentioned steps like for example
precious stone diamond is hardly
ever seen in form of beads so for
this gem drilling step makes no
difference. Similarly, for gemstone
comprising infinitesimal inclusions,
two almost same steps like grinding,
sanding gets clubbed into one.
Gem cutting process involves
lapidary techniques that convert
bleak rough into eye-catching
gemstone. The well-defined gems then
are used in distinctive ways viz.
cabbing, faceting and carving. Be an
adjunct with the above-mentioned
techniques, the below text also
mentions about the different shapes
and mixing styles practiced in the
gemstone industry.
Lapidary Techniques
These are the
first and foremost techniques of
this crucial process where rough is
lightly hammered to confiscate
unwanted part like brittle and
fractured area of the stone. It is
performed in eight different stages
starting from sawing, grinding,
sanding, lapping, polishing,
drilling and tumbling.
SawingAs the name specifies, in
sawing a saw or cutter is used to
convert rough into small stones. The
saw is sharp circular blade made up
of steel, copper or phosphor bronze
alloy and its surface periphery
comprises diamond clench. It is
infused in the rough and then
whirled at many thousand feet for
every minute to make the gemstone.
After heating in order to remove
unwanted material from the stone, it
is washed with either with water or
oil. Washing helps stone and saw
from getting overheated. This entire
process requires lots of
concentration and expertise, one
single mistake can result in severe
damage. Therefore, intense
precautions are taken while sawing.
It is brutal to hold the rough with
naked hands while sawing;
consequently the person covers hands
and face with appropriate safety
gadgets.
There are mainly two types of saws
viz. circular and jig. According to
the rough and the gemstones to be
retrieved the saws are selected.
Saws are available in different
sizes.
[A] Circular Saws : These are the
most common saws used by gem cutters
as it is suitable for the majority
of roughs. The edge of the saw is
plane and sharp. There are three
different types of circular saws.
[a] Slab Saw - Slab saw consists of
16-24 inches diameter. It is used
for cutting thick rough into thin
slab stones.
[b] Trim Saw - Trim saw possesses
6-10 inches of diameter. It is used
for cutting smaller roughs into
small stones.
[c] Faceter's Trim Saw - This saw
has minimum diameter that is of 4
inches, least amongst all. It is
used for cutting the most valuable
rough into small stones.
[B] Jig Saws As the name
specifies, the edge of the saw is
jig jag that is helpful in cutting
curved lines in the rough. It is
used along with a thin metal band or
wire. This saw minimizes the wastage
therefore is mostly used for costly
stones like
Ruby,
Emerald,
Alexandrite and so on.
Grinding Once the rough is sawed
into small stones then after each
single stone is rubbed against
either diamond - infused or silicon
carbide wheels to bestow the
preferred outward appearance. This
is referred as preform. At this
stage many times the surface of the
stone is left with undesirable
scratches. Subsequent to grinding
the unwanted grits and mesh are
removed by cleaning the preform with
water or oil. It also acts as
coolant as it averts the stones from
excessive heat.
Sanding In this stage the stone
gets the flat and smooth surface.
Through the use of excellent
abrasives, the graze and scratches
are removed from the stones that are
left behind in the previous step. It
is the crucial step for shaping the
stone as from now the perfection in
final appearance begins.
LappingThis step of gem cutting
process is quite similar to previous
two steps that is grinding and
sanding. The stones are stroked
against one side of either gyratory
or vibrating flat disk in order to
give the flat surface. The disk is
made up steel, cast iron and copper
bronze alloy etc. It is known as
Lap.
Polishing It is the most important
step as after this step the
gemstones attain the mirror like
appearance that helps in light
reflection from its surface area.
Different types of polishing agents
are used for defining the overall
look of the stone. Alumina, cerium
oxide, tin oxide, lead, ferric
oxide, chromium oxide and silicon
oxide etc are few names of the
polishing agents used by the gem
cutters. Ferric oxide also known as
jeweler's rouge and silicon oxide
called as tripoli are mostly used.
According to the surface of the
stone the polishing agent is
selected for example flat surface
stones are polished with tin oxide,
lead, pellon or leather. For round
surface felt, leather, cork or cloth
is used.
Drilling As the name specifies, in
this step a small hole is created
through the stone, such stones are
known as beads. Only some semi
precious stones are used for making
the beads as precious stone and
other semi precious stones like
alexandrite etc are too expensive.
Small revolving rod or else tube
with a diamond or silicon carbide
tip is inserted to drill the hole in
the stone. Silicon Carbide consists
of 9.5 Mohs while diamond is 10 Mohs
on the hardness scale. The former is
the synthetic compound of silicon
and carbon. This manmade amalgam is
used mostly for softer gemstones.
Ultrasonic or vibrating drills are
the most effective source for
drilling the gems but are used
exclusively for huge amount of
beads, as it turns too costly for
making small number.
Tumbling It is the mode of giving
the desirable attractive shape to
the stone that are formed roughly in
the lap of natural environment.
Large numbers of unappealing shaped
stone are turned in a tumbling
barrel at a dawdling speed along
with abrasive silicon carbide and
water for days together. Stones are
rinsed vigilantly between the grades
there by attaining the smooth and
polished look. There are two ways
for tumbling the gemstones. One is
rotating while other is vibrating.
Rotator Tumbler These are the
barrels hexagonal in shape that aids
in the rotation of the gems. In
rotator tumblers the gems are turned
fully upside down. In order to know
the progress of the gems inside the
tumbler, it has to be brought to a
standstill in regular time duration.
Rotating tumbler is standard
tumbling method and is cost
effective too.
Vibratory Tumbler These barrels
are like a container in which the
gems are in the stationary position
but are vibrated from all sides. It
is quite easy to monitor the
progress of the gems inside this
tumbler as compared to the rotator
tumbler.
Faceting
The aim of faceting is to
reveal the vividness and luminosity
of a gem. It refers to the light
refraction in the stone that is when
light ray enters from one of the
facet of the stone it is reflected
back for the bottom facet. The
viewer in rainbow colours views this
light refraction. Proper faceting is
very important for the transparent
stones such as diamond, ruby,
peridot, sapphire, topaz and many
others. Well-created facets in the
stone amplify its net value
magnificently.
An individual creating the facet is
known as facetor. He/she cuts and
polishes the facet on the intact
surface of stone using the faceting
machine. The machine consists of a
motor that holds the hand piece
assembly by rotating the lap, water
supply and adaptable hand piece along
with index gears, protractor and
mast/platform. There are two types
of faceting machines - one is left
that is known as mast- type and
other is right faceting machine. The
later is further having two
varieties viz. hand piece and
platform.
The flat surface of the gem is known
as facet. Each facet on the stone is
created in a proportioned pattern.
First the facetor immerses the
gemstone in the adhesive wax, epoxy
or glue and sticks it on a metal
dipstick. Later it is placed in the
hand piece to get the position
control. Then after cutting angle is
adjusted vertically with the help of
the protractor while rationally it
is done through index gear. Finally
then facets are created after
grinding, sanding and polishing on
the revolving lap. In the regular
intervals water and other solutions
are used as coolant and lubricant
respectively. This cycle completes
one side of stone. A jig is used to
change the side on the dipstick. In
the same way by repeating the steps
opposite side is finished too.
Normally flat facets are seen but
with modern technology and
innovative ideas of facetors,
new-fangled concave facets, grooves
and much such novel stuff are
created.
Cabbing
It is also known as
cabochon cutting, the simplest and
most common lapidary form. Opaque
and translucent stones are designed
in this variety. Transparent stones
with too many inclusions are also
cut into cabochons to use it
optimally. Cabochon at top are
smoothly curved and polished while
on bottom it is flat or round that
could be polished or sanded as per
the jeweler's requirement.
Turquoise, opal, bloodstone, lapis
lazuli etc are mostly shaped into
cabochon.
Cabbing procedure is almost same as
faceting. Cabochons or cabs are cut
through the process of dopping where
the stone is attached to the
dipstick with the help of either
adhesive wax or glue. Later the
stick along with the stone is
rotated during all the lapidary
techniques to have the smooth
rounded surface all over the stone.
Dopstick is made up of metal or
wood. Separate cabbing machines are
also available. These machines
consist of quite a lot of wheels
having diamond or silicon carbide
gravel, twirled by one single arbor
and motor. It also has a continuous
water supply that acts as a
coolant/lubricant to rinse off
unwanted fragments and protects the
stone from excessive heat.
Carving
It is a creative art in
born in the carving artist. It is
the most difficult art as the
craftsmanship involves deep
concentration, patience and
imaginative skills. Apart from these
talents he/she must also possess
methodical knowledge about the
lapidary techniques then only they
could give astonishing look to their
respective artwork. One who carves
the costly gems is a skilled
individual, turning the plain stone
into captivating masterpiece having
the functional or decorative use.
Semi precious stones are suitable
for carving as precious stones are
extremely valuable and pricy. There
are many different types of carvings
done on the gemstones. Some of the
most common ones are :
CameosStones and sea shells are
referred as cameos. It is the carved
portraits in any size of the stone.
The portrait is carved above the
surface of the gemstone. It seems
striking because of the natural
colored layers and remarkable
carving. The wonderful blend of
God's creation and human art in one
single frame looks amazing. Semi
precious stone Agate is most
commonly used for making this
carving item however; some fine
artist also brings other stones into
play. Italy and Germany are the main
source of premium cameos carved from
shell and agate stone respectively
across the globe.
IntagliosThis art conception is
quite similar to that of cameos. It
is carved on gemstones and seashells
as well. The difference between the
two is of carved portraits.
Intaglios are the portraits that are
carved down into the surface of the
stone while the portraits are raised
above the stone surface in cameos.
The beauty of the carving emerges
due the different coloured layers
displayed in the stones through the
natural formation. Italy and Germany
again are the preeminent foundation
of eye-catching art pieces of this
form of carved item.
SculptureThese are the carved
forms of living things, it may be
any animal, bird or even the human
face or body. This is solely created
and procured to decorate unusual
corners of the dream home. It is
mentioned especially for dream home
because sculptures are relatively
classy and pricey when compared with
other carved forms.
It is priced high due to three
reasons. First, creating a sculpture
requires extreme expertise and
artistic skills, as all the organs
of the living creature should be
well defined. There is no scope for
minute errors or slight change else
the final look of the art piece
differs from the look of the living
being. Artists take months to do
fine detailing of their masterwork.
Second reason is the cost of the raw
material. The main raw material for
carving sculpture is the stone. The
price of the stone itself is very
high. Further, the cost increases
with the increase in the size of the
stone. Moreover, for creating any
size of carving the stone turns out
to be more costly than the wood or
clay. If it is carved on the single
stone then the price is increased
more. Finally the third reason,
additional use of other coloured
stones or diamonds to give it more
natural look makes the price touch
the sky.
Stand Alone CarvingThese are the
carving pieces that are not used for
making jewelry items. They are
created for decorative purpose or
for some practical use such as ash
trays, jewelry boxes, pen stands,
key chains, paper weights and so on.
These fine-looking objects are
always in demand by the gemstone
lovers.
Beads
These are engraved as small
spheres first and later drilled to
make beads that could be string
together in a string to make the
diverse jewelry items like necklace,
earrings and hand bracelets etc. In
order to make spheres, the
lapidarist saws cubes or
dodecahedrons from the rough. The
cubes then are shaped into round by
grounding it between the rotating
concave cutters. The stone revolves
around the concave cutter
irrespective of the direction and
attains the desired spherical shape.
The spheres formed, then undergo the
lapidary process of grinding,
sanding and polishing. Finally,
these are drilled to form the beads.
Once the beads are formed, it is
taken over to bead mills for
grinding and sanding in order to
make high quantity commercial beads
together at the same time. As a
final point, these are polished
through tumbling. Bead mill consists
of two laps viz. one grooved while
other flat. The spheres turned into
beads are rolled between these laps
to obtain the perfect pet shape.
Mixing Styles
The universe is
crammed in with immense talent.
People across the world use their
groundbreaking ideas in each and
every field like computer, fashion
and so on. Similarly, gemstone
industry too has billions of
artisans who create
attention-grabbing art pieces using
their pioneer thoughts be it for
jewelry items, functional items or
decorative pieces. Artists mix
different coloured stones in one
single art work in a distinctive
technique. Few such inimitable
examples of mixing styles are
inlays, mosaics and intarsia.
Inlays Inlays are created by
mixing gemstones with materials like
metal, wood and other stones. The
gemstone is cut in the favored
shape, glued with the adhesive wax
and then fixed into a void nook of
other materials as mentioned. This
style only uses opaque stones as the
beauty of these lies in its façade
that is only the outer appearance
visible to the viewer. Semi precious
stones commonly used as black onyx,
turquoise, jade and so on.
Transparent stone requires some ray
of light that refracts along
different facets, sparkles and looks
fabulous. Therefore, transparent
stones are not suitable as in an
inlay once the stone is fixed it has
no scope of any light rays.
Intarsia and MosaicsThis is the
unique style of mixing that involves
innovative and creative designing
skills. Both these art pieces are
crafted by joining together the
coloured stones small in size like
pebbles on a flat base material like
stone, wood and metal etc. All the
stones are top cut and polished in a
way that it looks like a picture. It
could also be set in some appealing
pattern that grabs the attention of
the viewer at the first glance.
Then main difference between these
two at forms is same as that of
cameos and intaglios. Mosaic is
produced on the top of plane base of
stone whereas intarsia is fashioned
into the surface of the foundation
material viz. stone, wood or metal.
The later is also called as
Florentine mosaic or Pietre Dure.
The name Pietre Dure suggests, the
finest pattern of this skilled
artwork is brought into being from
the land of artists called as Italy.
Shapes
As cited, in the ingenious
world both the artist and the end
user are passionate about new and
unusual designs. The regular shapes
like round and square still exist
and shall subsists forever but the
demand for something new is
increasing at a very rapid pace.
Thus, everyday new shapes are
created as per the demand of the
coloured stones enthusiasts.
Round This is the standard shape
quite common in faceted stones as
well as cabochons. It is mostly used
as a center stone in necklace or
ring fingers. The beauty of this
shape increases with the increase in
size of the stone.
Oval
 Oval is the most universal
shape in the jewelry items as it
compliments all other shapes very
well. It adds an exclusive look to
the designs. In cabochons, this
shape is idyllic and the
exquisiteness of the stone is
highlighted very well. All opaque
stones get very well cut in this
shape. It goes well even for faceted
stones.
SquareIt is yet another regular
shape but less common than the
previous two. It is suitable only
for those designs that are created
with respect to the square cut gems.
This shape does not match well with
other shapes rather has its own sole
significance.
RectangleThis shape is little
unusual for regular jewelry designs,
same as square. However, it could be
seen in cabochons as well as in
faceted stones. Big size single
stone cut into rectangle shape hung,
as a pendant in a thick black or
multi-coloured thread looks quite
trendy and is ideal for the casual
wear.
EmeraldIt is initially cut as
rectangle then the four corners are
sliced away to give an emerald cut.
This is relatively a new shape being
like by young generation. Precious
stone Emerald in this shape is in
style amongst the elite families of
the society. The attractiveness of
this shape too increases with the
increase in the size of the stone.
MarquisIt is a new creative
shape, thin at the edges and thick
in between of the stone body. The
top and bottom of the stone are
curved pointed points. Transparent
stones are more suitable for this
shape than the opaque gems. Female
finger rings with gemstones cut in
marquis shape are gaining popularity
in every corner of the globe. It is
also referred as Navettes.
ShieldThis shape is proportioned
at the sides of the stone but the
ends are cut in diverse directions.
It is available in different
magnitude and varied sides. This is
relatively less known and atypical
shape.
CushionIt is shaped similar to
the cushions of the sofa or divan in
the drawing room. It is more or less
like either square or rectangle with
its sides smoothly curved. This
shape is more used for transparent
stones.
Tear DropThis shape is like a
drop of water or tear thus named so.
It is pointed at the top and curved
as semi circle at the bottom. This
is a bizarre shape therefore need to
be clubbed along with other shapes
to intact the design for any jewelry
item. It is also called as pear
shape.
Geometrical ShapesGeometrical
design jewelries are new-fangled
choice of selection amongst the
younger generation who seek fun and
frolic in their trendy style. These
designs are created using all
different shapes of the geometry
like triangle, hexagon, octagon,
rhomboids, parallelograms and many
more. The most remarkable part of
these deigns is that it makes
fabulous pendants for males.
Normally, females dominate jewelries
but as for geometrical jewelries it
is mostly for males.
Fancy Shapes
 These shapes are
fashioned into jewelries that define
the sophisticated and elegant aspect
of women. The shapes are customized
as per the requirement of the user.
Few to name are leaf cut shape,
princess cut, animals, alphabets,
symbols and so on. Leaf cut shape is
actually the shape of a new leaf of
any tree; gold or silver sleek wires
highlight the veins in the leaf.
This cut is mostly made in light
coloured stone such as
peridot,
amazonite etc. The absolute gaze of the
shape is very charismatic and it
represents the skilled craftsmanship
of the artist. Similarly, the
alphabets are shaped in different
varieties of calligraphy. The fancy
shapes has indefinite boundaries, it
all dependence on ones ideas and
thoughts.
This is long journey that the
gemstone covers from being found in
the lap of Mother Nature to the end
possessor. The entire process is
intricate and requires attention to
the minute details. The hard work
and creativity invested gives birth
to the beauty.
(Image Courtesy:
GemsDB.com)
More Resources
Step by step Gem cutting guide
Gem cutting
company
Gemstone cutting terms
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