This natural ruby undergoing local in expensive treatment by of
large numbers and sizes, initially the Americans & Japanese resisted
these repaired rubies, because of non disclosure of the treatment.
There are many companies who are producing some lead glass (repaired)
rubies. There are chances of more unusual features as many companies
have begun these treatments. The glass composition may vary in future
as some producers are just mixing lead oxides powders, with different
f1uxes, silica quartz, crushed glass on different rubies. Some companies
had already been treating sapphire heated with beryllium technology.
Many Thai scientists from different universities researched to develop
a glass compound suitable to repair fissures in rubies. Whereas
the Natural ruby with such looks are prohibitively expensive, hence
an alternate for those who can afford and also be informed. The
scarcity of natural ruby initially lead to heat, diffusion and now
glass filling (Paw Mai) known locally as the new treatment, in rubies,
flooding the market with good looking in expensive rubies. It is
a multi step treatment involving simple heating using different
lead rich compounds to fill the fissures and cavities of the stones.
The gems are preformed warmed up to 900-1400C to burn the impurities
in the fissures. The rubies are then mixed with some oxides powder
(silica, lead with sodium, potassium etc) and heated. The Orange
powder will turn into yellow orange glass after heating. The second
type of formation has some metallic oxides optimizing the color
in the rubies. This formula is in fact a mixture of much oxide powder
is added carefully with an oil to cover the rubies, and then rubies
are placed in the crucible and heated in a furnace. The powder will
use into the glass, and there are possibilities of better fillers
in the future. There are many kinds of changes, it is vulnerable
and requires special knowledge and security, precaution as the lead
finnes can be toxic. The rubies are preformed and heated again using
lead glass as such getting the rubies better results. They are finally
cut and polished. Identification: Apart from advanced tests it may
be easy for now to identical under magnification, the filled areas
show blue or orange flashes, the gems are filled with plate less
and gas bubbles like both matching color-orange, some times the
iron stains which are orangish become black and whitest after treatment.
Controlled treatment may give even better, results, and may become
difficult in future to identify these most sought gems. It is also
felt it is ethical to sell the glass filled, provided the customer
is disclosed about. These days glass filling in rubies has led to
new avenues and many other gems are about to join this cosmetic
presentations, in the trade there are reports that these rubies
normally selling from Rs 100 to 1,000/ct in the sizes from 1 ct
to 90 cts. There are reports that these are well flooded in India
and China
|