| THE BIRTHSTONE for SEPTEMBER (Blue) | |
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The 5th and 45th ANNIVERSARY STONE |
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The 70th ANNIVERSARY JUBILEE STONE |
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MOH's scale of hardness : 9 |
Toughness : Excellent |
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Refractive Index : 1.762-1.770 (+.009,-.005) |
Specific Gravity : 4.00 (+.10,-.05) |
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Sapphire and Ruby comprise more than half of all Gemstones sold worldwide. Sapphire's popularity is not based on color alone. Its hardness of
9 places it next to Diamond (10), making it an excellent choice for jewelry
worn daily. It is frequently featured in engagement rings.
Most people relate Sapphire to the color Blue. Sapphire is a form of Corundum
(ko-RUN-dum), readily available in an array of other colors:
Blue, Pink, Golden, Green,
peachy Orange, Purple and Colorless. These alternate colors are called 'Fancy
Sapphire', or simply variations of the standard hues. Color change
Sapphires are those which have two colors which are distinct when the light
source is changed from fluorescent to incandescent. Generally, the
more clear and vivid the color, the more valuable the fancy sapphire.
If the color is in the pastel range, the clarity should be good: because
in lighter tones any inclusions are more noticeable. The trade usually recognizes gemstones with fewer visible inclusions
to be more valuable than gems with visible inclusions. In a lighter
colored gemstone, the cut is also more important: it should reflect light
back evenly across the face of the stone, making it lively and brilliant.
With darker more intense colors, the cut isn't as critical because the
color creates its own impact. Sapphire is not usually heat sensitive, but a
jeweler's torch could alter the color, it may be prudent to ask a Jeweler to
remove the stone before applying his torch. There are not very many chemicals
that could attack this gem, but if boiled in a diamond cleaning kit the stone
can lose it's polish, also Jewelers pickling solutions containing borax will
etch the surface.
Although everyone has heard of the fabled Burmese Kashmir Sapphire, few
have ever seen one. We constantly see appraisals that refer
to Kashmir Sapphire (or Cashmere Sapphire), but it is usually referring to a Top
Gem Ceylon Sapphire from Sri Lanka. The term Kashmir is widely regarded to mean
the finest quality Blue Sapphire with a velvety, slightly violetish blue, highly
saturated in medium to medium dark tone, with sleepy transparency. Once in a great while we are able to acquire
one from Burma, but since the
mine has been depleted and these highly prized stones are old stones that
are simply brought back onto the market, they don't last long. Authentic
Kashmir Sapphires and the Kashmir color Sapphires carry a particularly high cost per carat and are very
highly valued Collectors Gemstones.
TREATMENTS - Almost
all (99%) Sapphire on the market is routinely treated
with 'heat' to enhance and stabilize the color. The typical heat treatment
process is a permanent process and it does not normally
adversely affect the performance, and durability of the gem, but
in recent years demand for natural non-heated non-treated top quality Sapphire
has caused these gems to command a somewhat higher premium, depending on the
gem. When we disclose a gem as enhanced with 'heat', we are
typically referring to the heat enhancement
procedure performed in Sri Lanka right near the mines, using the lower temperature
wood heat method. This 'blow' heat method typically is used on very very
good quality Ceylon gems, only to slightly enhance the color and/or to
stabilize the color from fading in sunlight. There's no need to worry when
you see this enhancement disclosed. Almost all
Ceylon Padparadscha Sapphire and virtually all Ceylon Orange Sapphire on the
market was subjected to 'blow' heat. This 'blow' heating method has been
an accepted trade
practice for many many generations. There are
other types of heat enhancement procedures, however, one of which is a high
temperature furnace fired method. This
'furnace' process is typically performed on Sapphire of a much lesser quality.
The goal is to seriously enhance or alter the color and/or clarity of the stone.
Most of these gemstones are 'cooked' over and over until the gem dealers feel it
is a more desirable color and will fetch a better price in the market.
We normally do not offer gemstones of this type.
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