Things to take care before buying precious
stones
Before Buy Lab Created Gemstones, diamonds or pearls, it is a good idea to
learn about the subject in order to recognize the differences that could affect
the value of your purchase. For example, some factors that can affect the value
of Lab Created Emerald are their size, if they are natural or created in the
laboratory, and if they were subjected to any treatment to improve their
appearance.
There are three primary types of stone products:
•
The precious natural stones that are created by nature and that can be
rare and expensive.
•
The stones created in the laboratory - also called synthetic, laboratorygrown, or manufactured - that possess the same chemical, physical, and visual
properties as natural gemstones, but are not so rare and are usually less
expensive than natural stones. They have similar characteristics. Example is
Man Made Emeralds
•
The imitation stones having a similar natural stone appearance, but can
be made of glass, plastic or another, cheaper material.
The stones created in the laboratory and those of imitation must be clearly
identified as such.
Size
Precious stones can be appraised according to their weight, their size or based
on both factors. The basic unit of weight of the precious stones is carate, which
is equivalent to 1/5 of a gram. The carates are divided into 100 units; each of
these units is called point. For example, a half-carate gemstone could weigh
.50 carats or 50 points. When the precious stones are measured according to
their dimensions, the size of the stone is usually expressed in millimetres
Treatments and enhancements
The treatments or enhancements refer to the way in which some stones are
treated to improve their appearance or durability, or even their colour. The
effects of some treatments on Synthetic Corundum may diminish or change
over time, and there are some treated stones that require special care. Some
enhancement treatments affect the value of a stone compared to a
comparable stone without treatment.
A jeweller should inform you if the stone you are interested in has been
treated:
•
If the treatment is not permanent.
•
If the treated stone requires some special care.
•
If the treatment significantly affects the value of the stone.
These are some common treatments and their effects:
•
The heat treatment can lighten, darken or change the colour of some
precious stones, or improve the clarity of the stone.
•
The irradiation treatment can add colour to colour diamonds, to certain
gemstones and to pearls.
•
The impregnation treatment consists of applying oils, waxes or
colourless resins and is used to hide a variety of imperfections and to improve
the clarity and appearance of the stones.
•
Fracture filling treatment is used to hide cracks in precious stones and
involves applying a plastic injection or colourless glass to improve the
appearance and durability of precious stones.
•
The diffusion treatment consists of adding colour to the surface of the
colourless gemstones; the centre of the stone remains colourless.
•
The dyeing treatment is used to add colour and improve the colour
uniformity of some gemstones and pearls.
•
The bleaching treatment is used to rinse and whiten some precious
stones, including jade and pearls.