No fire high quality common opal not from Virgin Valley. From Region East of Reno old collection. Not treated polished or otherwise altered. No repairs or glue solid inside the stone. Photos are of actual chunk for sale except one flake from the same stone to show transparency / translucency. Same as found except washed. Miocene about 7 million years old. All the stone is opal and it is all petrified wood. Very rare to see one this large. Cutting and polishing grade. Opal not agate or chalcedony. Surface has some weathering and cracking as is normal for opal found on the surface not mined. Many parts preserve original structure / rings. Weighs about 45 pounds maybe very slightly less or a little more. Stable will not crack or deteriorate if not left out in the weather for years.