metamorphic
Tiffany Stone
Fluoritized Opal Beryllium Ore (principally Bertrandite, Be4Si2O7(OH)2)
Hardness: 4-7 (highly variable); Color: Purple, lavender, white, cream, and black swirls; Luster: Vitreous to waxy; Crystal Structure: Amorphous (opal) to Orthorhombic (bertrandite); Cleavage: None; Specific Gravity: 2.1 - 2.6.
- Hardness
- 4-7 (highly variable)
- Color
- Purple, lavender, white, cream, and black swirls
- Luster
- Vitreous to waxy
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 4-7 (highly variable); Color: Purple, lavender, white, cream, and black swirls; Luster: Vitreous to waxy; Crystal Structure: Amorphous (opal) to Orthorhombic (bertrandite); Cleavage: None; Specific Gravity: 2.1 - 2.6.
Formation & geological history
Formed through the hydro-thermal replacement of limestone or volcanic ash by fluorine-rich fluids containing beryllium. These deposits in Utah are roughly 25 million years old (Miocene epoch).
Uses & applications
Primary source of industrial beryllium (used in aerospace and electronics); highly prized by lapidaries and jewelry makers for cabochons and as a rare collector's specimen.
Geological facts
It is also known as 'Ice Cream Opalite' or 'Bertrandite.' It is only found at the Brush Wellman Beryllium Mine in the Topaz-Spor Mountains of Utah, which is closed to the public.
Field identification & locations
Identify by its distinctive purple 'swirl' or 'cobweb' patterns and waxy texture. It is extremely rare because the mine crushes almost all extraction for beryllium processing, leaving very little for the specimen market.
More like this
