Treatments and synthetics
Fracture filling of cracks and removal of inclusions. Surface cracks fractures and cleavages reaching the surface can be filled with a glass-like material with similar RI.. Identification: when examined with an optical microscope, filled stones will show: greasy appearance, flash effects, bubbles.
Problem: Filling does not always resist polishing, heating, cleaning, age wear and tare Drilling of inclusions involves using a laser to drill into the inclusion. Solutions can be poured into the resulting "hair-width" diameter hole to bleach colored inclusions. This is compared to getting a filling in your tooth.
Irradiation is used to change the color of the diamond. A common color produced by irradiation are greens yellow and blues, usually very intense and not natural looking.
Synthetic diamonds are often yellowish in color (rarely used for gem purposes, more commonly used as diamond grit for industrial purposes. Modern synthesis of thin film diamond has other industrial applications).
A 5 mm diamond (0.5 carat) takes over a week to grow. Synthesis requires:
- high pressure
- high temperature
- a special apparatus
Synthetic diamonds can sometimes be distinguished from natural diamonds by the presence of flux inclusions (Ni, Al or Fe).
Simulants - That try to simulate the appearance of diamond
The distinction between a synthetic diamond (man-made diamond consisting of carbon atoms arranged in the typical diamond structure) and a diamond simulant (not a carbon compound with the diamond structure) is very important!
In order of increasing R.I., the most common simulates are:
- YAG = yttrium aluminum garnet
- GGG = gadolinium gallium garnet
- CZ = cubic zirconia
- Strontium titanate
- Diamond.
Another diamond stimulant is synthetic moissanite (Silicon carbide or carborundum) it was introduced to the jewelry market in 1998 it is one of the better simulates to date, but displays double refraction and may turn yellow under the heat of a low flame.
synthetic diamond jewelry
source: http://www.pink-diamonds.com.au/text.php?id=jewelry_diamonds_facts
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