Opal - Profound Glass - Austin TX

Manufacturing process for synthetic opal.

Mr Pierre Gilson started to study synthetic opals based on the information published by Dr Darragh and others thesis. In 1972, he succeeded in synthesizing opals, and two years after in 1974 Pierre Gilson started to sell this man-made opal to the public as Gilson Synthetic Opal. In the first place, white opals came in the market. Black opals followed next and subsequently he succeeded in producing transparent crystal opals (water opal). These synthetizing method involve a kind of flocculation method.

First, you add a little ethyl silicate into boiled weak alkaline solution and colloidal silica will grow. After separating and eliminating the condensed coarse spheres, by a sedimentation method, you drip ethyl silicate through a cooling installation and you grow amorphous silica spheres using colloidal silica as seed. You need a few months to get growth of uniform spheres and also you have to check the growing spheres all the time by a spectrometer. For this purpose, checking and modifying the temperature, density, and pH of the solution is very important. You stop the dripping of the ethyl silicate when sphere diameter becomes around 550nm. Then you continue to boil them a few more days and the effects are concluded.

After you collect and remove alchohol by distillation, you transfer the suspending solution, which contains the grown-up spheres into the clear container, such as a beaker. Then you let them settle down quietly over a long period of time. It takes a few months for the spheres to settle into a regular pattern. Centrifugal force cannot be used to accelerate settling of spheres. A few months later you will see the play of color displayed by the settled spheres in the beaker.

After you aspirate and remove most of the upper solution, you must add some more fluid containing colloid silica and stir the spheres up then for a second time to allow settlement start. First, settled spheres in the beaker become the cores and the later settlings grow upward as columns. At this time, the superior column eliminates the inferior column. In mineralogy, we explain these as geometric selection (Grigorlev 1965) and honeycomb color patterns get larger and larger.

The settled spheres exist in gel conditions and moisture is only slowly removed by natural evaporation so that dryness takes a long time. The gel turns into solid condition by the heat treatment until the gel becomes silica-stacked spheres of amorphous silica. Under this process, you can make black opal and transparent crystal opals by adding several additives. It takes about one year for the whole process.


Character of Gilson synthetic opals.

The characteristics of natural opals are varied and depending upon where they come from. The composition of both natural and synthetic opals are generally the same, of course, it is silica. The specific gravity of synthetic opal is little higher than natural opal. The reason seems to be due the difference of water content. Hardness of synthetic opal is slightly higher than natural ones. The refractive index of both opals are almost the same. Gilson synthetic opals play of color is very clear and beautiful.

Some times very good quality synthetic opals are equal in beauty to that of natural ones. Gilson synthetic opals spheres grow vertical in the bottom of the container with the columnar structure forming by natural settlement. While growing, the angle of columns will change from one to other column because of the principal of "geometrical selection".

These differences in the angulation of columns in Gilson synthetic opal may explain why you can observe the "lizard skin", when you observe them in their vertical angle of growth. If you cut Gilson synthetic opal according to the vertical angle of color pattern growth direction and polish them, you can observe the typical honeycomb structure, which is called "lizard skin" under the optical microscope. This is the distinctive feature of synthetic opals from the naturally occurring opals.

These coin opals are flat & polished on both sides and rounded & polished along the edges. Each stone flashes a rainbow of intense fire. You are going to love these opals!
Price: $7.75 ea

Brand: Gilson created opal #2
This piece of Gilson opal rough has a black base and lots of red and blue fire. It measures 18.5mm wide x 42mm long x 6mm thick. The opal weighs 8.2 grams.
Price: $492.00 . . . (= $ 60 / gram)

Brand: Gilson created opal #9
This piece of Gilson opal rough has a black base and lots of green, gold and red fire. It measures 15mm wide x 42mm long x 6mm thick. The opal weighs 5.3 grams.

Price $318.00 (= $ 60 / gram)

Our Black 6mm opal beads have a black base color and flash every color of the rainbow. These opals are fully drilled and ready to be strung and worn.

Why use our created opal beads? Unlike other synthetic opal beads, these opals will not discolor over time and are amazingly durable. You can wear them, wash them, and keep on moving--they will not lose their color or dull. How do we know? We embed them in molten glass! Talk about a durability test. Invest a little upfront and enjoy these beautiful opals for life.
Price: $30.00 ea