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Tiffany Stone / Opalized Fluorite / Bertrandite
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Opal Fluorite rough 9/25/11 - 01 - From my cutting stash... 1 LARGE - SUPER Nice - TOP GRADE GEM SLAB. Exceptional slice. This is an AWESOME but slightly tapered piece - excellent good cutting quality - you will not see many like this. In the 3rd & 4th pictures, the white areas in the center are pitted and soft.
5.5 x 4 x .3 to .2 inches - 210 gram

You are bidding on Rare Rough Opalized Fluorite! This material is one of the most scarce, beautiful and unusual stones in the world, this stone only comes from one very small area of beryllium mines in the Utah west desert where they mine (the 4th lightest element) beryllium for use in missile nose cones and many other high-tech metallurgical uses. It is not open to the public for collecting and very little of this material sees anything other than the ore crusher to extract the about 1% to 2% beryllium contained in the opal tuff. Try to find this exquisite gemstone and you'll see that it's not only very rare, it is very scarce. It is a soft to hard opalized stone that forms in very small to 100+ pound "nodules", composed of predominantly opalized fluorite (blues, purples and whites), often with many other minerals such as quartz, dolomite, rhodonite, manganese, beryllium and other surprises. It often has a "crackled" appearance and is sometimes called "Tiffany Stone", "Bertrandite" "Purple Opal" or "Ice Cream Opalite". I call it Opal-Fluorite. This material has become very scarce. Get it while you can.