This polished Blue Star Thunderegg shows brecciated rhyolite filled with translucent agate with gentle feathery bands in white to pale blue. The surface is scattered with tiny open vugs that reveal hints of crystal druzy.

The chalcedony shows green fluorescence under 365nm ultraviolet light.

Polished Surface: 9.5cm x 5cm 
Approx. 1.25" deep

5.6oz

Blue Star Thundereggs are a recent find out of Sonora, Mexico. They have a dark grayish to reddish brown outer rind with blue chalcedony inside, typically with a prevalent classic thunderegg star pattern. Many nodules are only partially filled, revealing open inner cavities showing botryoidal formations of chalcedony and crystal druzy inside.