admin answers:
Opalite may have a manmade contemporary, but in Nature, Opalite is made up primarily of naturally occurring Dolomite and Fluorite and a little Quartz, and it resembles natural Opal, in that it is very shiny and of a very pretty lavender or purplish color, usually.
Natural White Opal is, by definition, every other variety of Opal NOT exhibiting the Black, or precious phase we think of when we think of Opal.
In reality, though, all Opal is the result of organic plant or living matter having been changed, through time, heat and UV radiation, as well as other natural forces, into a shiny, soft and easily worked or flaked stone having some really spectacular characteristics.
Opal is composed of naturally occurring Silica Dioxide and hydrogen and oxygen. The stone is splendid in that it is found in virtually any and all colors imaginable and the chemical formula for this remarkable stone is: SiOnH2O, which translates into "A jelly like crystallized mineral having a Lot of water in it and it is soft". Natural Opal can have as much as 20% of water in it or very much less, around 2 % or 3 %.
For gem-making, you would not want a very high water content, as this stone will crack badly upon drying, ruining the gem later on. I have found and seen fossilized, entire trees composed almost completely of light color or "White Opal", and most especially in the Columbia River Gorge of Washington and Oregon... Rock hounds would practically kill just to find such a specimen.
