2009 Momentum - Glashütte Original

Time Study Sapphires and rubies
During these processes, about half of the corundum material is
lost as dust.
Then the blanks go through a series of operations performed by
qualified personnel: evening the thickness, forming the exteriors,
beveling, faceting, spherical or cylindrical recessing and doming,
polishing, cleaning, and quality control. It is only after all of these
just about 20 steps have been completed that an imperfection in
a crystal can be seen and declared usable or not. The blanks are
cleaned between each step to ensure that particles of sapphire
residue from the diamond cutting wheels, diamond powder and
cementing resins are completely removed. Any of this left on the
blank will affect the quality of each machining operation. The most
important cleaning step takes place after the final operation. This
allows for a proper visual control of the transparency of the piece
and ensures that only perfect crystals are delivered to the customer.
32 Momentum 1· 2009
Senator Sixties Technical data
Glashütte Original’s designers have captured
the joie de vivre of the 1960s in the
Senator Sixties, greatly characterized by
the domed dial and crystal typical of the
period – though then it would have been
Hesalite rather than sapphire, the latter a
material far more resistant to scratching –
which allow the extra-flat case premium expression
that perfectly matches the arced,
luminescent, skeletonized hands gliding
harmoniously across the satin-finished dial
with diamond-cut hour markers and extra -
vagant numerals. The shaped sapphire crystal
case back allows a direct view into automatic
manufacture Caliber 39-52 with its
characteristic elements of Glashütte watchmaking
such as three-quarter plate and
swan-neck fine adjustment. This timepiece
is available with a silver-coloured or black
dial in a rose gold or stainless steel case.
www.glashuette-original.com
The beauty of blue
sapphire lies in the
rich colour of this
corundum variety
Anti-reflective coating is an option for sapphire
crystals. This diffuses every reflection so that the naked eye sees
almost no reflection. The coating is actually a layer of oxide between
three and five microns thick added to the crystal by an evaporation
system in a sterilized laboratory at a temperature of about 280°C.
The crystals can be made anti-reflective either on the underside or
on both sides, and the difference is astounding when you compare
the two side by side. If the watch sports a blue or black dial, an
anti-reflective coating on both sides can almost make the wearer
believe that there is no crystal at all. Likewise, if anti-reflective treatment
is missing, a blue or black dial may prove hard to read. One
drawback of anti-reflective treatment is that it is softer than the
sapphire crystal itself, meaning that although it may be close to
impossible to scratch the crystal – which only a diamond can do
– the anti-reflective coating can easily be scratched. Crystals treated
on one side are 92% anti-reflective, while crystals treated on both
sides are 96% anti-reflective.
Synthetic rubies, today’s standard as bearing jewels,
are, by the way, manufactured the same way. The red boules are
literally sliced using a machine outfitted with a copper and diamond
cutting tool. The slices are halved, squared, and finally cut into
round shapes measuring between 0.3 and 0.5 millimetres in thickness
and 1.15 to 2.55 millimetres in diameter.
Using synthetic sapphire crystal as a watch dial covering became
popular in the late 1960s as it could boast three distinct advantages
over the acrylic and mineral crystals that had mainly been used
until then. Synthetic sapphire is hard – the second hardest substance
available – and therefore can only be scratched, or worked,
by a diamond. Synthetic sapphire is heavy, giving a watch a more
luxurious feel. And synthetic sapphire is still a precious stone, albeit
man-made, making the watch more valuable as a whole – much like
the perception that ruby bearings in a movement exude. ✺