Jeweller - August 2021

Lapidary Design | GEMSTONE FEATURE
L to R: 'Starbrite' Mixed cut Oregon
sunstone by John Dyer; Asscher
cut citrine by Doug Menadue;
Cabochon jade, 1stDibs; princesscut
garnet by Magus Gems;
trillion-cut morganite by John
Dyer; lapidary worker polishing
boulder opal; lapidary machine
into the table, surrounded by a black extinction
halo with the true colour of the stone only
revealing itself in small areas along the outside
edge of the stone.
This cut is a weight-saver so it can be found
on all types of stones. Popular stones that are
readily found with this cut would be tourmaline,
tanzanite, amethyst, kunzite, and aquamarine.
» Cabochon – The Cabochon is the oldest cut for
coloured gemstones. It’s the only cut on this list
that isn’t a faceted stone.
The top of the stone is a dome that can be shallow
or deep. The bottom is flat or slightly rounded to
fit into a bezel setting.
A cabochon can also be cut as a Sugarloaf,
which means that it has four sides – like a
rounded pyramid – which gives an effect like a
smooth, colourful piece of candy. The benefit of
the Cabochon is that it ‘glows’ colour, whereas a
faceted gemstone shines.
The Cabochon is often used for lower-quality
transparent material that isn’t as useful for
faceting, though for certain materials such as
jade and opal, the most premium colours and
clarities of the gemstone become the most
beautiful in a Cabochon cut.
Cabochons are also the optimum cut for
displaying phenomenal effects such as stars,
cat’s-eyes and adularescence, which are not
visible without a dome shape. The Cabochon
was once the only cut and its popularity still
continues today.
Every stone can be found as a cabochon but
highlights include jade, star ruby and sapphire,
opal, emerald (especially as a Sugarloaf),
turquoise, cat’s-eye chrysoberyl, moonstone,
and labradorite.
» Trillion – The Trillion cut is a three-sided
triangular cut and is one of the only styles on
this list that is dependent on the shape.
The cutter might choose to use this shape for a
piece of rough gem that is naturally three-sided.
The cutting style is usually a Mixed cut with
a Brilliant crown and either a Brilliant,
Portuguese, or Step cut pavilion.
If the stone is cut on top and bottom in the
Brilliant style then sometimes the name can
be written as ‘Trilliant’.
The benefit of the Cabochon
is that it ‘glows’ colour,
whereas a faceted gemstone
shines... For certain materials
such as jade and opal, the
most premium colours and
clarities of the gemstone
become the most beautiful in
a Cabochon”
The benefit of this cut is that since it has
an odd number of sides, each side reflects
the light of the two opposite sides making
Trillions naturally brighter and more sparkling
than other styles.
The Trillion cut is less common than some other
styles on this list, so you don’t see as many
gemstones readily available in this cut.
The gemstones that you are likely to find
are tanzanite, aquamarine, topaz, amethyst,
and tourmaline.
» Princess – The Princess cut is essentially
a Brilliant cut for square stones. Since the
Brilliant cut is composed of triangular shaped
facets, it doesn’t fit inside of square shapes.
So, in the early 1900s, gem cutters created this
design to be able to give the square shape the
same brilliant sparkle that they were able to
achieve for round shapes.
The Princess cut started as a popular cut
for diamonds but now is used for coloured
gemstones and works very well for brightening
up dark material – though you don’t often see
it used.
It can be used on a square, rectangular
or Emerald cut outline, and gives much
more flash and light return than a Step
cut, but at the cost of losing extra carat
weight in the process.
Sapphires are sometimes cut as Princess cut
because they are frequently sold on shelves next
to diamonds and the cut name often attracts the
eyes of diamond buyers.
However, any dark-toned stone would
benefit from a Princess cut, such as spinels,
tourmalines, and garnets.
» Star – The Star cut is a useful cut that lies
somewhere between a Brilliant cut and a
Portuguese cut.
Essentially, it’s a Brilliant cut that is given an
extra set of facets on the pavilion that can help
soften and diffuse lighter colours such as yellow,
pink, and peach.
It’s a cut that is often used in India and Sri Lanka
but is quite useful on pastel coloured gemstones
that might otherwise become too light with a
normal Brilliant cut.
The Star cut also has the benefit of giving the
46 | August 2021